Duke Case Review Clearscan Part 1

Front 1

A 26-year-old woman with malaise and night sweats.

Back 1

DIFFERENTIAL DIAGNOSIS
• Lymphoma: This is the most Likely diagnosis given the
age of the patient, appearance of the mass, and associated
para tracheal adenopathy.
• Thymoma: This is less Likely because these lesions usually
occur in older patients, are typically more focal and
unilateral, and are not associated with right paratracheal
adenopathy.
• Germ cell tumor: A primary germ cell tumor of the
mediastinum cannot be definitively excluded on the
basis of age or radiologic appearance. However, associated
adenopathy makes lymphoma more Likely.
Radiologic features that suggest germ cell tumors are
fat and calcification.
• Metastatic disease: Although the mediastinum is a
common site of metastatic disease from testicular germ
cell tumors, renal cell carcinoma, or melanoma, the
middle mediastinum is preferentially involved.
DIAGNOSIS: Hodgkin's lymphoma.
KEY FACTS
CLINICAL
• At least 50% of patients with Hodgkin's lymphoma
have intrathoracic lymph node disease.
3
• At least 90% of those with intrathoracic disease have an
anterior mediastinal mass.
• Pleural disease is unusual at presentation.
RADIOLOGIC
• Hodgkin's lymphoma typically manifests as a lobulated,
anterior mediastinal mass that most Likely represents
matted lymph nodes. Associated mediastinal
lymphadenopathy is common and is a key differentiating
feature from thymoma and germ cell tumor.
• Intratumoral calcification is rare in patients with
untreated lymphoma.
• Lung parenchymal involvement in the absence of hilar
or mediastinal adenopathy is rare before therapy.
+ SUGGESTED READING
Fraser RG, Pare JAP. Diagnosis of Diseases of the Chest (2nd ed).
Philadelphia: Saunders, 1979.
Heitzman ER. The Mediastinum: Radiologic Correlations with
Anatomy and Pathology. St. Louis: Mosby, 1977.
North LB, Libshitz HI, Lorigan JG. Thoracic lymphoma. Radiol
Clin North Anl 1990;4:745-762.
Tecce PM, Fishman E 1<., Kuhlman JE. CT evaluation of the anterior
mediastinum: Spectrum of disease. Radiographies 1 994;14:
973-990.

Front 2

Asymptomatic 45-year-old woman with a history of breast carcinoma.

Back 2

DIFFERENTIAL DIAGNOSIS
• Metastatic breast carcinoma: Isolated metastatic disease
to the right paratracheal nodes is an unusual manifestation
of breast carcinoma. Biopsy is required, however,
as metastatic disease cannot be definitively
excluded.
• Bronchogenic cyst: The most likely diagnosis given
the location and predominantly cystic appearance.
• Lymphadenopathy: Low-attenuation para tracheal
adenopathy can result from central necrosis due to
tumor or infection (mycobacterial, fungal). Necrotic
nodes are typically more heterogeneous and may have
an enhancing rim.
+ DIAGNOSIS: Bronchogenic cyst.
+ KEY FACTS
CLINICAL
• Bronchogenic cysts, also known as foregut malformations,
are congenital anomalies caused by abnormal
budding of the tracheobronchial tree.
• They are typically lined by bronchial and respiratory
mucosa but can contain gastric mucosa as well. They
are filled with variable amounts of mucus, protein, and
cellular debris.
• They can be associated with esophageal duplication
cysts and sequestrations.
• Bronchogenic cysts are usually asymptomatic but can
enlarge and produce symptoms by compression of
adjacent mediastinal structures.
• No treatment is necessary unless the patient becomes
symptomatic.
RADIOLOGIC
• Bronchogenic cysts most commonly occur in the subcarinal
and right para tracheal regions.
• They usually manifest as smooth, well-marginated
mediastinal masses on chest radiographs and CT.
5
• They are typically homogeneous on CT. Fifty percent
are of water attenuation, and 50% are of sofr-tissue
attenuation due to intracystic hemorrhage or proteinaceous
debris.
• On MRI, they are usually of high signal intensity on
T2-weighted images. Signal intensity on Tl-weighted
images is variable depending on the presence of hemorrhage
or protein (high signal intensity).
• Air-fluid levels are rare and are usually due to infection
or instrumentation.
+ SUGGESTED READING
Fraser RG, Pare JAP. Diagnosis of Diseases of the Chest (2nd ed).
Philadelphia: Saunders, 1979.
Heitzman ER. The Mediastinum: Radiologic Correlations with
Anatomy and Pathology. St. Louis: Mosby, 1977.
Naidich DP, Rumancik WM, Ettenger NA, et al. Congenital anomalies
of the lungs in adults. AJR Anl J Roentgenol 1988 ;1 5 1 :
1 3-19.
Patel SR, Meeker DP, Biscotti CV, et al. Presentation and management
of bronchogenic cysts in the adult. Chest 1994; 1 05 :79-85 .
St. Georges R, Deslauriers J, Duranceau A , e t al . Clinical spectrum
of bronchogenic cysts of the mediastinum and lung in the adult.
Ann Thorac Surg 199 1 ;52:6- 1 3 .

Front 3

A 33-year-old woman with mild upper back pain.

Back 3

DIFFERENTIAL DIAGNOSIS
• Neurogenic tumor: A neurogenic tumor is the most
common cause of a posterior mediastinal or paravertebral
mass.
• Neuroenteric cyst: This is unlikely since there are no
vertebral body anomalies.
• Paraspinal abscess: This is unlikely in a minimally
symptomatic patient without radiologic evidence of
vertebral body destruction or disk space narrowing.
• Localized fibrous tumor of pleura: This is a rare pleural
tumor that can manifest as a paraspinal mass. These
tumors are often pedunculated and can be quite large.
They are typically of heterogeneous attenuation on CT.
• Extramedullary hematopoiesis: This usually manifests
with bilateral, lobulated paraspinal masses in a
patient with severe anemia.
• Lymphoma: Isolated paraspinal disease is an uncommon
manifestation of thoracic lymphoma.
• Metastatic disease: Isolated metastatic disease to the
pleura or mediastinum is less likely than a neurogenic
tumor given the minimal symptomatology and no history
of a primary malignancy.
+ DIAGNOSIS: Neurofibroma.
+ KEY FACTS
CLINICAL
• There are three groups of neurogenic tumors of varying
malignant potential: peripheral nerve tumors (schwanno-
7
mas, neurofibromas, malignant nerve sheath tumors),
sympathetic ganglia tumors (neuroblastomas, ganglioneuroblastomas,
ganglioneuromas), and paragangliomas.
• Schwannomas and neurofibromas are the most common
neurogenic tumors of the posterior mediastinum.
• Malignant degeneration (malignant nerve sheath
tumor) is rare.
• Patients with schwalmomas or neurofibromas can be
asymptomatic or present with back pain.
• Multiple peripheral nerve tumors are usually associated
with neurofibromatosis.
RADIOLOGIC
• The peripheral nerve tumors (schwannomas and neurofibromas)
manifest as round, paravertebral masses
that span two vertebral bodies or less. They may
invade the neural canal. Rib erosion is common. They
manifest as homogeneous, soft-tissue attenuation masses
on CT.
• The tumors of the sympathetic ganglia manifest as
elongated paraspinal masses, spanning multiple vertebral
levels. Intratumoral calcification is common in
these tumors.
• SUGGESTED READING
Fraser RG, Pare JAP. Diagnosis of Diseases of the Chest (2nd ed).
Philadelphia: Saunders, 1979 .
Heitzman ER. The Mediastinum: Radiologic Correlations with
Anatomy and Pathology. St. Louis: Mosby, 1977.
Reed JC, Hallett K.K, Fcigin DS. Neural ntmors of the thorax:
Subject review from the AFIP. Radiology 1 978;1 26:9-17.

Front 4

A 6 1 -year-old man presents with progressive shortness of breath.

Back 4

DIFFERENTIAL DIAGNOSIS
• Pleural metastatic disease: Metastatic disease is the
most common malignancy of the pleura. However, the
appearance of diffuse pleural thickening and a tumor rind
is more suggestive of mesothelioma than metastases.
• Malignant pleural mesothelioma (MPM): This is the
most likely diagnosis given the age of the patient, the
radiologic appearance of the mass, and the evidence of
prior asbestos exposure (pleural plaques).
• Loculated empyema: This patient had no signs and
symptoms of empyema. The degree of pleural thickening
argues for a long-standing process.
+ DIAGNOSIS: Malignant pleural mesothelioma.
+ KEY FACTS
CLINICAL
• MPM is rare. There are approximately 1,500 new cases
in the United States each year.
• Patients usually present with increasing dyspnea in the
sixth to seventh decade of life.
• There is a 5 to 1 male-female ratio.
• Treatment options are limited, and the prognosis is
dismal, with a median survival of 12 months.
9
• There is a high association with prior asbestos exposure.
• There is no relationship with smoking.
RADIOLOGIC
• MPM manifests as a unilateral pleural mass, which can
be focal or diffuse, surrounding the hemithorax.
• MPM is often associated with a pleural effusion.
• Contralateral pleural plaques from prior asbestos exposure
may be identified.
• Local invasion of the chest wall, mediastinum, or
diaphragm is common.
• L ymphadenopathy occurs with more extensive tumor
and in the later stages of disease.
• Intra-abdominal extension and contralateral lung or
brain metastases are unusual features.
+ SUGGESTED READING
Achatzy R, Beba W, Ritschler R, et al. The diagnosis, therapy and
prognosis of diffuse malignant pleural mesothelioma. Eur J
Cardiothorac Surg 1989;3 :445-448.
Legha SS, Muggia F. Pleural mesothelioma: Clinical features and
therapeutic i mplications. Ann Intern Med 1977;87: 6 1 3-62 l .
Patz EF, Shaffer 1<., Piwnicka-Worms DR, et al. Malignant pleural
mesothelioma: Value ofCT and MR imaging in predicting
resectability. AJR Am J Roentgenol 1992 ; 1 59:961-966.

Front 5

A 63-year-old asymptomatic man

Back 5

DIFFERENTIAL DIAGNOSIS
• Calcified hemothorax: This is unlikely because a calcified
hemothorax is usually focal and unilateral.
• Old empyema: These are also typically focal and unilateral.
A calcified empyema is usually due to prior
tu berculosis (TB).
• Asbestos-related pleural disease: This is the most
likely diagnosis given bilateral calcified pleural plaques.
DIAGNOSIS: Asbestos-related pleural disease.
KEY FACTS
CLINICAL
• Patients with plaque disease are usually asymptomatic.
Dyspnea can result from very extensive pleural disease
(diffuse pleural fibrosis) or be associated with interstitial
fibrosis (asbestosis).
• Patients with asbestos-related pleural disease are at
increased risk for malignant pleural mesothelioma and
lung cancer.
• Plaques usually arise from the parietal pleura. The visceral
pleura is uncommonly involved.
11
• The frequency and number of plaques is thought to be
a dose-dependent phenomenon.
• Pleural plaques are usually seen 20 years after asbestos
exposure.
RADIOLOGIC
• Bilateral calcified pleural plaques are virtually pathognomonic
for asbestos-related pleural disease. The
plaques are usually larger and more numerous in the
mid- and lower hemithoraces.
• They can be associated with rounded atelectasis, malignant
pleural mesothelioma, and bronchogenic carcinoma.
• Plaques often calcifY, although this may not be evident
on plain radiographs.
• SUGGESTED READING
Fraser RG, Pare JAP. Diagnosis of Diseases of the Chest (2nd cd).
Philadelphia: Saunders, 1 9 79.
Goodman PC. Asbestos-Related Lung and Pleural Disease. In
AR Margulis, CA Gooding (cds), Diagnostic Radiology.
St. Louis: Mosby, 1 9 8 5 ; 1 5 5- 1 64.
Greenberg SD. Asbestos lung disease. Semin Respir Med
1982;4 : 1 30- 1 37.

Front 6

A 35-year-old woman status post bilateral lung transplantation for pulmonary
hypertension.

Back 6

DIFFERENTIAL DIAGNOSIS
• Infection: This is less likely because graft infection is
uncommon in the first week after transplantation.
• Reimplantation response: This is the most likely cause
of diffuse airspace opacities occurring in the first few
days after transplantation and resolving within a week.
• Acute rejection: This is less likely because the radiographic
manifestations of rejection are WlCommon in
the first week after transplantation.
+ DIAGNOSIS: Reimplantation response to lung
transplantation.
+ KEY FACTS
CLINICAL
• Possible causes of the reimplantation response include
graft ischemia, lymphatic or vascular disruption at the
time of surgery, or graft denervation.
• It is a diagnosis of exclusion.
• Other complications, such as acute rejection and infection,
are usually not seen until 5 to 10 days posttransplantation.
13
• Most graft infections in the first month posttransplant
are bacterial. Thereafter, cytomegalovirus
pneumonia and fungal pneumonia are more common.
RADIOLOGIC
• Radiographically, the reimplantation response usually
begins within 2 days of surgery, peaks at 4 days, and
resolves within a week.
• The radiographic appearance varies from subtle, perihilar
linear opacities to diffuse consolidation. Pleural
effusions are common.
SUGGESTED READING
Herman SJ, Rappaport DC, Weisbrod GL, et al. Single lung transplantation:
Imaging features. Radiology 1989 ; 1 70:89-9 3 .
Herman SJ. Radiologic assessment after lung transplantation. Clin
Chest Med 1990; 1 1 : 3 3 3-346.
Medina LS, Siegel MJ, Glazer HS, et al. Diagnosis of pulmonary
complications associated with lung transplantation in children:
Value of CT vs. histopathologic studies. AJR Am J Roentgenol
1 994;162 :969-974.
O'Donovan PB. Imaging of compljcations of lung transplantation.
Radiographies 1993 ; 1 3 :787-796.

Front 7

A 25-year-old man and a 60-year-old woman with cough, fever, and chest pain.
Both have a history of recurrent pneumonia in the same pulmonary segment

Back 7

DIFFERENTIAL DIAGNOSIS
• Infected bronchogenic cyst: The multilocular nature
of the opacity argues against an intraparenchymal
bronchogenic cyst.
• Congenital cystic adenomatoid malformation
(CCAM): Although the location and appearance of
the lesion is consistent with this diagnosis, CCAM is
very rare in adults.
• Intralobar sequestration (ILS): This is the most likely
diagnosis given the history of recurrent pneumonia
and the radiologic demonstration of a systemic vascular
supply to the infected segment.
DIAGNOSIS: Intralobar sequestration.
KEY FACTS
CLINICAL
• n.s typically manifests in young patients with signs
and symptoms of recurrent pneumonia.
• ILS usually occurs in the posterior or medial basilar
segments of the lower lobes.
• ILS is more common on the left than the right (6 to 4 ) .
RADIOLOGIC
• On chest radiographs, ILS commonly manifests as a
focal, parenchymal consolidation. Air-fluid levels are
also common.
15
• Other, less common, manifestations include a focal
mass or a hyperlucent segment (sometimes with a central
mucus plug).
• By CT, MR!, or ultrasound, ILS usually manifests as a
unilocular or multilocular cystic mass. Solid masses are
sometimes seen.
• ILS is usually supplied by a systemic artery arising
from the abdominal or thoracic aorta, lumbar arteries,
or celiac axis. Venous drainage is usually via the pulmonary
veins. Inferior vena cava or azygous venous
drainage is less common.
• Diagnosis of ILS is made by radiologic demonstration
of systemic vascular supply. This can be accomplished
with angiography, contrast-enhanced CT (spiral CT is
best), or MR!.
SUGGESTED READING
Felson B. Pulmonary sequestration revisited. Medical Radiography
Photography 1988;64:1-27.
aidich DP, Rumancik WM, Ettenger NA, et al. Congenital anomalies
of the lungs in adults: MR diagnosis. AJR Am J Roentgenol
1988;15 1 : 1 3- 1 9 .
Panicek D M , Heitzman ER, Randall PA, e t a l . The continuunl of
pulmonary developmental anomalies. Radiograprucs
1987;7:747-772.

Front 8

A 50-year-old man with cough and hemoptysis.

Back 8

DIFFERENTIAL DIAGNOSIS
• Bronchial carcinoid tumor: This is the best single
diagnosis given the radiologic appearance of the mass
and the sclerotic rib metastasis.
• Lung cancer: Although lung cancer cannot be excluded,
the central calcification and sclerotic metastasis are
more suggestive of bronchial carcinoid.
• Lymphoma: Lobar atelectasis is a very uncommon
manifestation of lymphoma. Central calcification also
argues against this diagnosis.
• Metastatic osteosarcoma: This could account for the
radiologic findings but is less common than carcinoid.
• Fibrosing mediastinitis: This can result in lobar
atelectasis but would not explain the sclerotic metastasis.
Also, fibrosing mediastinitis usually manifests as a
calcified, infiltrative process, not a focal mass.
+ DIAGNOSIS: Metastatic bronchial carcinoid tumor.
+ KEY FACTS
CLINICAL
• Eighty-five percent of carcinoid tumors occur within
the central bronchi (central carcinoid); 15% arise distal
to segmental bronchi (peripheral carcinoid).
• Peripheral tumors manifest as asymptomatic pulmonary
nodules.
• Central tumors manifest with symptoms of bronchial
obstruction such as hemoptysis, chest pain, or recurrent
pneumonia.
• Bronchial carcinoid tumors are rarely associated with
paraneoplastic syndromes such as carcinoid syndrome,
Cushing's syndrome, or acromegaly.
• Carcinoids are histologically divided into two types:
typical (75% to 90%) and atypical (10% to 25%).
17
• The prognosis for typical carcinoid tumors is excellent.
The prognosis for atypical carcinoid tumors is less
favorable.
RADIOLOGIC
• Peripheral tumors manifest as solitary, well-circumscribed
pulmonary nodules.
• Central lesions manifest as hilar masses with or without
obstructive atelectasis or pneumonia.
• In some cases, a small endobronchial component is
associated with a larger exobronchial component. This
is termed the "iceberg" phenomenon.
• Calcifications, central and chunk-like, are seen by CT
in up to 26% of cases.
• On T2-weighted MR images, bronchial carcinoid
tumors have a very high signal intensity.
• Uptake by 1131 metaiodobenzylguanidine (MIBG) or
indiumll1 pentetreotide can also be seen.
• A typical carcinoid manifests as a small mass «2.5 cm
in diameter) with no associated adenopathy.
• An atypical carcinoid manifests as a larger mass (>2.5
cm) with localized adenopathy.
+ SUGGESTED READING
Forster BB, Muller NL, Miller RR, et al. Neuroendocrine carcinomas
of the lung: Clinical, ractiologic and pathologic correlation.
Radiology 1 989;1 70:440-445 .
Muller NL, Miller RR. Neuroendocrine carcinomas o f the lung.
Semin Roentgenol 1990;25:96-104.
Zwiebel BR, Austin JHM, Grimes MM. Bronchial carcinoid tumors:
Assessment of location and intratumoral calcification in thirtyone
patients. Ractiology 1 991;279:483-486.

Front 9

A 65-year-old man with a long history of sinus disease presents with cough, fever,
and hemoptysis.

Back 9

DIFFERENTIAL DIAGNOSIS
• Infection: Likely organisms include postprimary
tuberculosis (TB ), chronic progressive fungal infection,
nocardia, and possibly anaerobic abscesses . Given the
radiologic findings, postprimary TB must be strongly
considered.
• Neoplasm: Potential neoplastic etiologies include
synchronous primary lung cancers (squamous cell
carcinoma ) , metastatic disease, or less likely, cavitary
parenchymal lymphoma ( Hodgkin's disease).
Potential primary tumors metastatic to the lung
include squamous cell carcinoma of the head and
neck, squamous cell carcinoma of the cervix, and
metastatic sarcoma. However, apical predominance is
uncommon in pulmonary metastatic disease .
• Vasculitis: Potential vasculitic etiologies include
Wegener's granulomatosis and, less likely, cavitary
rheumatoid nodules. The historic clue of chronic
sinus disease makes Wegener's granulomatosis a likely
diagnosis.
DIAGNOSIS: Wegener's granulomatosis.
+ KEY FACTS
CLINICAL
• Wegener's granulomatosis is a multisystem granulomatous
vasculitis.
• Major sites of involvement include the sinonasal cavity,
lungs, and kidneys.
19
• Elevated c-ANCA (antineutrophil cytoplasm antibody)
titers are sensitive and specific for active Wegener's
granulomatosis.
• Wegener's granulomatosis has a good prognosis with
aggressive medical management.
RADIOLOGIC
• Patients typically present with multiple pulmonary
nodules or masses. One-third to one-half of nodules
cavitate .
• The disease can also manifest a s focal o r diffuse
parenchymal consolidation . Diffuse pulmonary hemorrhage
is the presenting manifestation in up to 10% of
cases.
• Involvement of the trachea and bronchi is uncommon
and can result in lobar atelectasis and bronchial
stenoses.
• Pleural effusions are uncommon and adenopathy is rare.
• New pulmonary opacities in a patient being treated for
known Wegener's granulomatosis suggest opportunistic
infection, either fungal or Pneumocystis carinii
pneumonia.
+ SUGGESTED READING
Aberle DR, Gamsu G, Lynch D. Thoracic manifestations of Wegener
granulomatosis: Diagnosis and course. Radiology 1990; 1 74:
703-709.
Warren J, Pitchenik AE, Saldana MJ. Granulomatous vasculitides of
the lung: A cl.injcopathologic approach to ctiagnosis and treatment.
South Med J 1989;82 :48 1 --49 1 .
Weisbrod GL. Pulmonary angijtis and granulomatosis: A review. Can
Assoc Ractiol J 1989;40 : 1 2 7- 1 34 .

Front 10

A 25-year-old woman with progressive dyspnea

Back 10

DIFFERENTIAL DIAGNOSIS
• Chest radiograph: Differential diagnosis based on the
chest radiograph includes sarcoidosis, pulmonary histiocytosis
X (PHX), tuberculosis (TB), pneumoconiosis,
and hypersensitivity pneumonitis .
• High-resolution CT (HRCT)-nodules: Differential
diagnosis for nodules on HRCT includes sarcoidosis,
PHX, hypersensitivity pneumonitis, pneumoconiosis,
TB, and various forms of bronchiolitis .
• HRCT -air cysts: Differential diagnosis for air cysts
on HRCT includes lymphangioleiomyomatosis, PHX,
Pneumocystis carinii pneumonia, bronchiectasis, and
"honeycomb " lung (idiopathic pulmonary fibrosis).
• The combination of nodules and air cysts on HRCT
makes PHX the most likely diagnosis.
DIAGNOSIS: Pulmonary histiocytosis X.
KEY FACTS
CLINICAL
• Also known as Langerhans's cell histiocytosis or
eosinophilic granuloma of lung.
• Patients are typically young to middle aged, with a
higher incidence in men.
21
• Patients typically present with cough and dyspnea. Twenty
percent present with a spontaneous pneumothorax.
• At least 90% of patients with PHX are cigarette smokers.
RADIOLOGIC
• Typical radiographic manifestations include nodular or
reticulonodular opacities in the mid- and upper lung
zones. Lung volumes are typically normal or increased.
Adenopathy and pleural effusion are uncommon.
• Typical HRCT findings include thick- or thin-walled
air cysts and 3- to 5-mm centrilobular nodules. The
cysts may coalesce into unusual shapes. Both cysts and
nodules are more common in the mid- to upper lung
zones, typically sparing the costophrenic angles .
• The combination of air cysts and 3- to 5-mm nodules
is highly suggestive of the diagnosis.
• SUGGESTED READING
BraWler MW, Grenier P, Mouelhi MM, et a1. Pulmonary histocytosis X:
Evaluation with high resolution CT. Radiology 1989; 1 72:255-258.
Lacronique J, Roth C, Battcsti JP, et al. Chest radiologic features of
pulmonary histocytosis X: A report based on 50 adult cases.
Thorax 1982;37 : 1 04-109.
Webb WR, Muller NL, Naidich DP. High Resolution CT of the
Lung. New York: Raven, 1 992;1 1 1 -1 3 3 .

Front 11

A 65-year-old man with progressive dyspnea and dry cough.

Back 11

DIFFERENTIAL DIAGNOSIS
• Usual interstitial pneumonia (UIP): This is the most
likely diagnosis because of the pattern of irregular linear
opacities, ground-glass opacities, traction bronchiectasis,
and honeycomb cysts in a peripheral distribution.
• Rheumatoid lung: In most cases, rheumatoid lung
cannot be differentiated radiologically from VIP. Key
radiologic clues to this diagnosis include pleural effusion
or rheumatoid nodules.
• Scleroderma lung: In most cases, scleroderma lung
cannot be differentiated radiologically from VIP. Key
radiologic clues to this diagnosis include soft-tissue calcifications
or a dilated, air-filled esophagus.
• Chronic hypersensitivity pneumonitis (CHP): In
many cases, CRP cannot be differentiated radiologically
from DIP. Key radiologic clues to this diagnosis
include small nodules or an upper lobe predominance.
• Asbestosis: In most cases, asbestosis cannot be differentiated
radiologically from VIP. Key radiologic clues to
this diagnosis include pleural effusion or pleural plaques.
• Pulmonary drug toxicity (nitrofurantoin, methotrexate,
bleomycin): In most cases, fibrosis from drug toxicity
cannot be differentiated radiologically from DIP.
+DIAGNOSIS: Usual interstitial pneumonia.
+ KEY FACTS
CLINICAL
• VIP typically manifests in middle-aged to elderly
adults with progressive dyspnea and dry cough.
• As many as 30% have a positive rheumatoid factor or
antinuclear antibodies without clinical signs of collagen
vascular disease.
23
• Twenty percent have associated collagen vascular disease.
• VIP is a progressive, fatal illness with a median survival
of 4 years.
• Corticosteroid and cytotoxic therapy is of limited benefit.
Lung transplantation is a viable option in appropriate
candidates.
RADIOLOGIC
• Typical chest radiographic manifestations of VIP
include bibasilar irregular linear opacities, honeycombing,
and volume loss.
• Adenopathy and pleural effusions are rare.
• There is poor correlation between radiologic abnormality
and clinical or functional derangement.
• On high-resolution CT, DIP manifests with irregular
linear opacities, ground-glass opacities, traction
bronchiectasis, and honeycomb cysts in a peripheral
distribution. This pattern of parenchymal involvement
is virtually diagnostic of VIP.
• It should be noted that fibrosis due to collagen vascular
disease, drug toxicity, and end-stage hypersensitivity
pneumonitis cannot be distinguished radiologically
from VIP.
+ SUGGESTED READING
Carrington CB, Gaensler EA, Couto RE, et aI. The natural history
and treated course of usual and desquamative interstitial pneumonia.
N Engl J Med 1 9 78;298:80 1-809.
Staples CA, Muller NL, Vedal S, et aI. Usual interstitial pneumonia:
Correlation of CT with clinical, functional, and radiologic findings.
Radiology 1 987;162: 377-38 1 .
Webb WR, Muller NL, Naidich DP. High Resolution CT of the
Lung. New York: Raven, 1 992 ; 1 1 1 - 1 3 3 .

Front 12

A 53-year-old woman with progressive dyspnea, cough, and low-grade fever over
the past 8 weeks.

Back 12

DIFFERENTIAL DIAGNOSIS
• Bronchiolitis obliterans organizing pneumonia
(BOOP): This is the most likely diagnosis given the
radiologic and clinical findings.
• Atypical pneumonia: Resolving mycoplasma pneumonia
is a less likely consideration.
• Eosinophilic pneumonia: Although eosinophilic
pneumonia should be considered, it usually manifests
with peripheral, upper lobe consolidation .
• Multifocal bronchioalveolar carcinoma ( BAC):
Although the radiologic appearance is consistent with
BAC, the clinical history makes BOOP more likely.
• Pulmonary lymphoma: Again, although the radiologic
appearance is consistent with lymphoma, the clinical
history makes BOOP more likely.
• Alveolar proteinosis: This usually manifests with
more diffuse, basilar opacities.
• Alveolar sarcoidosis: The age of the patient, the clinical
signs and symptoms, and the lack of adenopathy
argue against sarcoidosis.
+ DIAGNOSIS: Bronchiolitis obliterans organizing
pneumonia.
+ KEY FACTS
CLINICAL
• Fifty percent of cases are idiopathic; the remainder
are associated with collagen vascular disease, drug
25
toxicity, toxic fume exposure, infection, or recurrent
aspiration .
• Idiopathic B O O P i s also known a s cryptogenic or,tJanizing
pneumonia. It manifests as a subacute illness with
cough, dyspnea, and low-grade fever.
• Restrictive abnormalities on pulmonary function testing
are common.
• Idiopathic BOOP responds well to steroids and has a
good prognosis.
RADIOLOGIC
• BOOP manifests with scattered air space consolidations
or ground-glass opacities. These are typically
peripheral and subpleural in distribution .
• Less common manifestations include nodules or irregular
linear opacities.
• Bronchial wall thickening or bronchiectasis is common.
• Pleural effusions are seen in up to 20% of cases.
+ SUGGESTED READING
Bellomo R, Finlay M, McLaughlin P, Tai E. Clinical spectrum of
cryptogenic organizing pneumonia. Thorax 199 1 ;4 1 : 554-559.
Epler GR, Colby TV, McLoud TC, et at. Bronchiolitis obliterans
organizing pneumonia. N Engl J Med 1985;3 1 2 : 1 52-1 58 .
Lee KS, Kullnig P, H artman TE, Muller N L . Cryptogenic organizing
pneumonia: CT findings in 43 patients. AJR Am J Roentgenol
1 994; 162: 543-546.

Front 13

A 3 5-year-old man with acute shortness of breath and a history of drug abuse.

Back 13

DIFFERENTIAL DIAGNOSIS
• Pneumocystis carinii pneumonia (PCP): This is a
possibility, particularly if the patient has acquired
immunodeficiency syndrome (AIDS) and a CD4 count
<400 mm3. The absence of adenopathy or pleural effusion
is consistent with this diagnosis. However, rapid
clearance is very atypical for PCP.
• Diffuse pulmonary hemorrhage (DPH): DPH cannot
be excluded radiographically. It can be associated
with drug abuse (inhaled or intravenous).
• Hydrostatic edema: The "bat's wing" distribution
and rapid clearance is consistent with this diagnosis.
Hydrostatic edema with normal heart size is seen in
patients with acute (first) myocardial infarction or cardiac
arrythmia.
• Permeability edema: This is the single best diagnosis
given the normal heart size and rapid clearance. Potential
etiologies in this patient include inhaled or intravenous
opiate abuse or inhalation of noxious gases (solvents).
+ DIAGNOSIS: Pulmonary edema due to inhaled
"crack" cocaine.
+ KEY FACTS
CLINICAL
• Patients usually present with acute shortness of breath
foUowing intravenous administration or inhalation of
crack cocaine.
27
• The mechanism of pulmonary edema is unclear.
Possible explanations include a direct effect on the
central nervous system leading to neurogenic pulmonary
edema, direct drug toxicity to the alveolar capillary
membrane, or an allergic response.
RADIOLOGIC
• Up to one-third of patients with opiate overdose
develop pulmonary edema.
• Rapid clearance is typical.
• Pneumomediastinum or pneumothorax is occasionally
seen.
SUGGESTED READING
Forrester JM, Steele AW, Waldron JA, Parsons PE. Crack lung: An
acute pulmonary syndrome with a spectrum of clinical and
histopathologic findings. Am Rev Respir Dis 1990;1 42:462-467.
Frand DI, Shim CS, Williams MK. Methadone induced pulmonary
edema. Intern Med 1 972;76:975-979.
Smith WR, Wells ID, Glauser FL, et al. Immunological abnormalities
in heroin lung. Chest 1975;68 :65 1-65 3 .
Steinberg A D , Karliner JS. The clinical spectrum o f heroin pulmonary
edema. Arch Intern Med 1968; 1 2 2 : 1 22-1 27

Front 14

A 40-year-old woman with a history of cigarette smoking and progressive dyspnea

Back 14

DIFFERENTIAL DIAGNOSIS
• Pulmonary histiocytosis X (PHX): This is unlikely
because the air "cysts" of PHX have well-defined walls
and are usually more numerous in the apices than the
bases.
• Lymphangiolieomyomatosis (LAM): This is unlikely
because the air "cysts" of LAM have well-defined
walls. Also, the intervening lung parenchyma is normal
in LAM.
• Centrilobular ( CL) emphysema: Tlus is not the best
diagnosis since CL emphysema affects the apices preferentially.
CL emphysema initially manifests as focal
(2 to 1 0 mm) lucencies without walls surrounding the
core lobular artery. These lucencies may later coalesce
into larger regions of decreased lung attenuation.
• Panlobular (PL) emphysema: This is the best diagnosis
since the bases are affected preferentially, the
lucencies have no walls, and there is no evidence of CL
emphysema. Although PL emphysema can be idiopathic,
many cases are related to alpha- I -antiprotease deficiency
(AIAD) and smoking.
+DIAGNOSIS: Panlobular emphysema due to
alpha - l -antiprotease deficiency.
KEY FACTS
CLINICAL
• Alpha- l -antiprotease (AlA) inhibits proteolytic
enzymes such as trypsin, elastase, and collagenase that
can cause emphysema. Patients with low levels of AlA
are at risk for early-onset of emphysema, and the risk is
increased in smokers.
29
• AIAD is an autosomal recessive disease. Homozygotes
have 1 0% to 1 5% of the normal AlA levels, and heterozygotes
have 60%.
• Almost all homozygotes develop early-onset emphysema
( age 35 to 50 years) . Smokers present 1 0 years earlier.
Heterozygotes can develop emphysema in the
presence of other risk factors.
• Histologically the emphysema is panlobular in type .
• There i s a n association with neonatal hepatitis and
cirrhosis.
RADIOLOGIC
• Radiographic evidence of panlobular emphysema is
seen in up to 80% of homozygous AIAD patients.
• PL emphysema is distinguished from air "cysts" by the
absence of perceptible walls. It typically manifests with
regional or generalized decreased lung attenuation.
The lung bases are preferentially affected.
• In A I AD , the lower lungs are affected in 98% of cases
and are the only site of disease in 24%.
• Bullae are an uncommon feature of AIAD .
SUGGESTED READING
Bergin CJ, Muller NL, Miller RR. CT in the qualitative assessment
of emphysema. J Thorac I maging 1986;1 :94-103.
Hepper NG, Mulm JR, Sheehan WC, et aI. Roentgenographic study
of chronic obstructive pulmonary disease by alpha - I - antitrypsin
phenotype. Mayo Clin Proc 1978;5 3 : 1 66-1 72 .
Rosen RA, Dalinka M K , Gralino B J , e t al. The roentgenographic
findings in alpha- I -antitrypsin deficency. Radiology
1970;95:25-28.
Webb WR, Muller NL, Naidich DP. Diseases Characterized by
Primarily Cystic Abnormalities, LWlg Destruction, or Decreased
Lung Opacity. In High-Resolution CT of the Lung. New York:
Raven, 1 992 ; 1 1 1-l 3 3 .

Front 15

A 23-year-old woman with sinusitis and recurrent respiratory infection

Back 15

DIFFERENTIAL DIAGNOSIS
• Cystic fibrosis ( CF): Not the most likely diagnosis
since bronchiectasis due to CF involves the upper
lobes to a greater extent than the lower lobes.
• Allergic bronchopulmonary aspergillosis (ABPA):
Also not the most likely diagnosis since ABPA typically
manifests with cylindrical or saccular central ( not
peripheral) bronchiectasis. Also, ABPA preferentially
involves the upper lobe bronchi.
• Postinfectious bronchiectasis: Childhood viral pneumonia
(adenovirus, measles), repeated aspiration, or
prior necrotizing pneumonias can also result in basilar
bronchiectasis. This is not the most likely diagnosis
given the clinical history.
• Primary ciliary dyskinesia ( PCD ): The clinical history
and radiologic findings of basilar bronchiectasis
and mucoid impaction make this the most likely
diagnosis.
+DIAGNOSIS: Primary ciliary dyskinesia.
+ KEY FACTS
CLINICAL
• Symptoms of bronchiectasis include chronic cough,
excess sputum production, and recurrent pulmonary
infection.
• Hemoptysis occurs in 50% of patients, usually due to
bronchial artery hypertophy.
• Aggressive medical therapy has largely obviated the
need for surgical resection of affected lobes.
31
• PCD is characterized by recurrent sinusitis, bronchiectasis,
and infertility. It results from a genetic defect in
the dyneil1 arms of the cilia.
• Fifty percent of patients with PCD have situs inversus
( Kartagener's syndrome) .
RADIOLOGIC
• Radiographic findings of bronchiectasis include parallel
lines (tram tracks), ring shadows, and mucus plugs.
• CT, especially high-resolution CT ( H RCT), is more
sensitive than chest radiography in the detection of
bronchiectasis. H RCT has also replaced bronchography
for this purpose .
• CT findings of bronchiectasis include bronchial wall
thickening and the signet ring sign. Visible bronchi in
the outer one-third of the lung are abnormal.
• CT can also suggest an etiology. Central bronchiectasis
suggests ABPA. Upper lobe bronchiectasis suggests
mycobacterial infection or cystic fibrosis. Basilar disease
suggests postinfection bronchiectasis, immune deficiencies,
or PCD.
+ SUGGESTED READING
Barker AF, Bardana EJ . Bronchiectasis: Update of an orphan disease.
Am Rev Respir Disease 1988 ; 1 37:969-978.
Schidow D. Primary ciliary dyskinesia. Ann Allergy 1994;73:457-468.
Westcott JL. Bronchiectasis. Radiol Clin North Am 199 1 ;29:
1 0 3 1 - 1 042.

Front 16

A 57-year-old woman with cough, progressive dyspnea, and fever of several
months' duration.

Back 16

DIFFERENTIAL DIAGNOSIS
• Bacterial pneumonia: The radiologic pattern is
unusual for bacterial pneumonia.
• Eosinophilic pneumonia ( EP): The clinical history
and distribution (peripheral and upper lobe) of opacities
makes this the most likely diagnosis.
• Postprimary tuberculosis (TB): TB must be strongly
considered given the radiologic and clinical findings.
However, the absence of cavitation makes TB less likely
than EP.
• Bronchiolitis obliterans organizing pneumonia
( BOOP): Because of the distinct upper lobe predominance,
EP is more likely than BOOP in this case.
• Pulmonary infarct (septic or bland): Although
infarcts are typically peripheral, they are usually wedgeshaped
and more numerous in the lung bases. Septic
infarcts also cavitate.
+ DIAGNOSIS: Chronic eosinophilic pneumonia.
+ KEY FACTS
CLINICAL
• EP results from alveolar and interstitial infiltration by
eosinophils and other inflammatory cells.
• Known etiologies include parasitic infestation, allergic
bronchopulmonary aspergillosis, drug reactions, and
pulmonary vasculitis ( Churg-Strauss syndrome ) .
33
• Idiopathic EP is divided into acute and chronic forms
depending on the severity and duration of symptoms.
• Chronic eosinophilic pneumonia ( CEP) usually occurs
in middle-aged women who present with several
months of cough, dyspnea, and fever. Two-thirds have
blood eosinophilia.
RADIOLOGIC
• CEP typically manifests with progressive air space consolidation
on chest radiographs. The opacities are usually
peripheral and upper lobe in distribution. The classic
"reverse pulmonary edema" pattern is seen in fewer
than half of cases.
• CT can be useful for demonstrating the peripheral
nature of the opacities.
• CEP is a remarkably steroid-responsive disease.
Symptoms and radiographic opacities usually resolve
within days. However, as many as 80% of patients
relapse following steroid withdrawal .
• SUGGESTED READING
Carrington CB, Adctington WM, et al. Chronic eosinophilic pneumonia.
N Engl J Med 1969;280:787-788 .
Dothager DW, Kollat MH. Peripheral infiltrates i n a post partum
woman. Chest 1993;99 :463-464.
Jederlinc PJ, Sicilian L, Gamsha EA. Chronic eosinophilic pneumonia:
19 cases and a review of the literature. Medicine
1988;154:62-69.

Front 17

Previously healthy 27-year-old woman presents with weight loss, malaise, and nonproductive
cough.

Back 17

DIFFERENTIAL DIAGNOSIS
• Sarcoidosis: The absence of significant intrathoracic
adenopathy makes this a less likely diagnosis.
• Metastatic disease: Metastatic nodules are usually more
variable in size. Possible primaries include thyroid,
breast, and pancreatic carcinoma as well as melanoma.
• Disseminated (miliary) tuberculosis (TB): The clinical
and radiologic fmdings are most consistent with
this diagnosis.
• Disseminated fungus: Although the radiologic findings
are also consistent with disseminated histoplasmosis,
coccidioidomycosis, blastomycosis, or cryptococcosis,
disseminated fungal infection most commonly
occurs in immunocompromised patients.
• Pneumocystis carinii pneumonia: This pattern would
be a less common manifestation in AIDS patients.
+ DIAGNOSIS: Miliary tuberculosis.
+ KEY FACTS
CLINICAL
• Symptomatic hematogenous dissemination occurs in
1 % to 7% of patients with TB.
• Miliary TB is more frequent in young children ( <2
years) , the elderly, and immunocompromised patients.
• Miliary dissemination usually occurs within 6 months
of the primary infection.
35
RADIOLOGIC
• The chest radiograph is usually normal at the onset of
clinical symptoms.
• Miliary TB usually manifests with diffuse, evenly distributed
1 - to 3-mm nodules. However, they may not
be visible until 6 weeks after dissemination.
• In 1 5% of patients, the distribution is asymmetric.
• The nodules usually have a perivascular and periseptal
distribution on CT.
• Intrathoracic adenopathy is seen in 95% of children
and 1 2% of adults.
• Associated consolidation is seen in 42% of children
and 1 2 % of adults.
• Response to appropriate antituberculous therapy is
typically rapid, with radiographic resolution within 4
to 6 weeks.
• SUGGESTED READING
McAdams HP, Erasmus JJ, Winter J . The radiographic manifestations
of pulmonary tuberculosis. Radiol Clin North Am
1995;33 :655-{)78.
Miller WT, Miller WT Jr. Tuberculosis in the normal host:
Radiologic findings. Semin RoentgenoI 1 993;28: 109- 1 1 8 .
Webb WR, MiUler NL, Naidich DP. High-Resolution C T of the
Lung. New York: Raven, 1 992.
Woodring JW, Vandiviere HM, Fried AM, et a!. Update: The radiographic
features of tuberculosis. AJR Am J Roentgenol 1 986;
148 :497-506.

Front 18

A 56-year-old man presents with fever, weight loss, and productive cough.

Back 18

DIFFERENTIAL DIAGNOSIS
• Aspiration: This commonly causes bilateral, multilobar,
poorly defined consolidation in dependent pulmonary
segments.
• Pulmonary malignancy: Postobstructive cavitary consolidation
can occur secondary to an endobronchial
neoplasm. A further possibility is bronchioalveolar
carcinoma.
• Wegener's granulomatosis: The most common
radiographic findings are nodular opacities with a
high propensity for cavitation . Pulmonary consolidation,
which may be scattered and heterogeneous, or
homogeneous and lobar, occurs in approximately
30% of patients.
• Pneumonia: Lobar consolidation is usually bacterial
in origin. The bacteria that commonly cause cavitation
are Staphylococcus au reus, Klebsiella, Pseudomonas)
Proteus) and anaerobic organisms. Mycobacteria tuberculosis
(TB) is increasingly a cause of consolidation
and cavitation.
DIAGNOSIS: Postprimary tuberculosis.
KEY FACTS
CLINICAL
• The highest incidence of postprimary TB is in patients
>65 years of age.
• Postprimary TB usually occurs due to reactivation of
dormant bacilli, although some cases may be due to
reinfection of a previously sensitized host.
• Reactivation occurs in 55% to 1 5% of patients, usually in
the secondary foci in the apical/posterior segments of the
upper lobes and superior segments of the lower lobes.
• Because of host hypersensitivity acquired from primary
infection, progressive disease with caseous necrosis
occurs and can rapidly destroy the lung.
• Most patients have a delayed cutaneous response to
the intradermal injection of purified protein derivative.
37
RADIOLOGIC
• The earliest findings are heterogeneous, poorly marginated
opacities in the apical or posterior segments of
the upper lobes or in the superior segments of the
lower lobes.
• The initial opacities usually evolve into more welldefined
reticular and nodular opacities.
• The infection may occasionally progress to lobar or
complete lung consolidation.
• Cavitation is common (40% to 87%) and typically
occurs within areas of consolidation.
• A complication of cavitation is endobronchial spread of
infection.
• Endobronchial dissemination results in 5- to 1 0-nun,
poorly defined peri bronchiolar and centrilobular nodules.
• Miliary TB occurs less commonly in postprimary than
in primary TB, and the classic radiographic findings are
diffuse, small ( 1 to 3 mm), well-defined nodules.
• Pleural effusions are uncommon ( 6% to 1 8% ) and usually
small.
• Hilar and mediastinal adenopathy is rare with postprimary
TB.
• Healing may be associated with scarring, cicatricial
atelectasis, traction bronchiectasis, residual nodules,
and parenchymal calcification .
• SUGGESTED READING
Armstrong P, Wilson AG, Dee P, Hansell DM. Imaging of Diseases
of the Chest (2nd ed). St. Louis: Mosby, 1995.
Fraser RG, Pare JAP, Pare PD, et aI. Diagnosis of Diseases of the
Chest ( 3rd ed). Philadelphia: Saunders, 1991 ;882-939.
McAdams H P, Erasmus JJ, Winter JA. Ractiologic manifestations
of pulmonary tuberculosis. Ractiol Clin North Am 1995;33:
655-678.
Miller WT, Miller WT Jr. Tuberculosis in the normal host:
Ractiologic findings. Semin RoentgenoI 1993;28: 1 09-1 1 8 .
Woodring JW, Vandiviere H M , Fried AM , e t a l . Update: The ractiographic
features of pulmonary tuberculosis. AJR Am J
Roentgenol 1 986;148 :497-506.

Front 19

A 75-year-old woman with mild dyspnea, chronic weight loss, and no history of fever.

Back 19

DIFFERENTIAL DIAGNOSIS
• Pneumonia: Lobar consolidation is usually caused by
bacterial infection. Organisms include Streptococcus
pneumoniae, Staphylococcus aureu.s, Legionella pneumophila,
gram-negative bacteria, and Mycobacterium
tuberculosis. A bacterial infection is unlikely with a history
of chronic weight loss and no fever, although
tuberculosis (TB) can have a subacute presentation.
• Aspiration pneumonia: Aspiration of gram-negative
or anaerobic bacteria may cause lobar consolidation.
Aspiration commonly causes scattered, poorly defined
consolidation in the dependent segments. I nvolvement
of the anterior portions of the lungs in this patient
makes this diagnosis unlikely.
• Wegener's granulomatosis: Although the disease can
be indolent, presentation is usually acute, with upper
airway involvement (sinusitis, rhinitis, otitis) and functional
renal impairment. Nodular opacities, which frequently
cavitate, are the most common presentation.
Lobar consolidation and numerous, small nodular
opacities occur in 30% of patients.
• Primary lymphoma of lung: This rare nonHodgkin's
lymphoma is usually low grade, and
patients are often asymptomatic. Consolidation with
air bronchograms and poorly defined margins is the
most common presentation. Mass-like and reticulonodular
opacities are less frequent.
• Bronchioalveolar cell carcinoma ( BAC): The clinical
presentation and homogeneous consolidation with
nodules could be due to the diffuse form of BAC.
+ DIAGNOSIS: Bronchioalveolar cell carcinoma.
+ KEY FACTS
CLINICAL
• BAC constitutes 1 . 5% to 1 0.0% of all lung cancers.
• It is a subtype of adenocarcinoma and can be localized
or multifocal. The localized form can, after an indolent
period of local growth, progress rapidly to diffuse tho-
39
racic metastases. The biologic behavior of BAC is,
however, controversial, and a further possibility is that
the two presentations are distinct, with the localized
form rarely evolving into diffuse BAC.
• Clinical features that distinguish BAC from other lung
cancers are ( 1 ) younger age at presentation, ( 2 ) equal
distribution of men and women, ( 3 ) copious watery
sputum ( bronchorrhea), and (4) higher incidence in
nonsmokers.
RADIOLOGIC
• The most common finding is a well-circumscribed,
solitary nodule (60%).
• The nodule may remain unchanged in size over many
years.
• The solitary nodule is usually peripheral in location.
• Pseudocavitation, the presence of small, low-attenuation
regions within or surrounding the nodule, is more
common with this malignancy than other non-small
cell carcinomas.
• The diffuse form may present as ( 1 ) multiple pulmonary
nodules of varying size; ( 2 ) focal, poorly
defined opacities resembling pneumonia; ( 3 ) reticulonodular
opacities resembling interstitial lung disease;
(4) other radiographic findings associated with
parenchymal disease include hilar and mediastinal
adenopathy ( 1 8%), pleural effusions ( 1 % to 1 0%), and
atelectasis ( 3 % ) .
+ SUGGESTED READING
Erasmus JJ, Patz EF. Diagnostic Imaging of Bronchogenic
Carcinoma. In C Chiles, C Putnam (cds), Pulmonary and
Cardiac Imaging. New York: Marcel Dekker, 1997.
Hill CA. Bronchioloalveolar carcinoma: A review. Radiology
1984; 1 5 0 : 1 5-20.
Kuhlman JE, Fishman EK, Kuhajda FP, et al. Solitary bronchioloalveolar
carcinoma: CT criteria. Radiology 1988; 1 67:
379-38 2 .
Miller WI, H usted J, Freiman D , e t al. Bronchioloalveolar carcinoma:
Two clinical entities with one pathologic diagnosis. AJR Am
J Roentgenol 1978;1 30:905-9 1 2 .

Front 20

Asymptomatic 71 -year-old man undergoes a routine annual chest radiograph

Back 20

DIFFERENTIAL DIAGNOSIS
• Malignancy: A primary pulmonary cancer and a single,
isolated metastatic nodule would be considerations
on the chest racliograph.
• Tuberculomas: Persistent mass-like opacities are an
uncommon manifestation of parenchymal tuberculosis
(TB ) . They are usually encountered in asymptomatic
adults. The majority ( 75%) occur in the upper lobes,
and they are usually <3 cm in size. Smaller satellite
lesions are seen in as many as 80%.
• Hamartoma: This is the best diagnosis because of the
focal collections of fat ( CT attenuation between - 40
and - 1 2 0 Hounsfield units [ H U ] ) .
• Arteriovenous malformations: These are single in
about two-thirds of cases. They are usually round,
sharply defined, and most often in the meclial third of
the lung. Size ranges from one to several centimeters
in cliameter. Identification of feeding and draining vessels,
which are essential to the cliagnosis, may be clifficult
to visualize on plain racliographs.
DIAGNOSIS: Hamartoma.
KEY FACTS
CLINICAL
• A hamartoma is a developmental malformation of clisorganized
tissues that normally constitute the organ in
which the twnor occurs.
• It has been proposed that they are best regarded as
benign neoplasms.
• Peak incidence is in the sixth decade, and they are
uncommon in patients <30 years of age.
• They most often occur in males (3 to 1 ) .
• Hamartomas are usually solitary, although multiple
pulmonary hamartomas can occur rarely in the multi-
41
pIe hamartoma syndrome ( Cowden's clisease) , which is
characterized by multiple mucocutaneous lesions and
gastrointestinal hamartomatous polyps.
• Carney's triad: ( 1 ) pulmonary chondroma (often multiple
) , ( 2 ) gastric leiomyosarcoma, and ( 3 ) extra-adrenal
paraganglioma, has been described. This occurs mostly
in women < 3 5 years of age.
RADIOLOGIC
• Hamartomas characteristically are well-defined solitary
nodules that are usually <4 cm in cliameter.
• The majority are located peripherally (90%), although
occasionally they may arise in the central bronchi.
• Calcification occurs in up to 50% and typically resembles
popcorn.
• The nodule may increase slowly over time; although
rapid growth can occur, it is rare .
• Cavitation is extremely rare.
• The presence of fat attenuation within tl1e mass, best
demonstrated on CT, is a cliagnostic feature. Fat may
be identified by CT numbers in the range of -80 to
- 1 20 H U .
• Fat may not b e present i n the hamartomatous nodule
in approximately one-third of cases.
• In the small percentage of centrally occuring hamartomas,
atelectasis and obstructive pneumonia may occur.
• SUGGESTED READING
Armstrong P, Wilson AG, Dee P, Hansell OM. Imaging of Diseases
of the Chest (2nd ed). St. Louis: Mosby, 1990;296-297.
Fraser RG, Pare JAP, Pare PO, et a1. Diagnosis of Diseases of the
Chest ( 3rd ed). Philadelphia: Saunders, 1991 ;882-939.
Poirier TJ, Van Ordstrand HS, et a1. Pulmonary chondromatous
hamartoma: Report of seventeen cases and review of the literature.
Chest 1971 ;59:50-5 5 .
Siegelman SS, Khouri N F , Scott WW, e t a l . Pulmonary hamartoma:
CT findings. Radiology 1 986; 1 60: 3 1 3-3 1 7 .

Front 21

A 52-year-old man presenting with a cerebral stroke.

Back 21

DIFFERENTIAL DIAGNOSIS
• Non-small cell carcinoma: The large size of the mass
and the age of the patient would favor this diagnosis
on the chest radiograph . The presence of enlarged vessels,
however, excludes the diagnosis.
• Metastatic lung disease: The solitary nature, large
size, and absence of a history of primary extrathoracic
malignancy would make this diagnosis unlikely.
• Arteriovenous malformation (AVM) : The welldefined,
lobulated contour, medial location, and identification
of feeding and draining vessel would be characteristic
for this diagnosis.
• Tuberculoma: This is usually in the upper lobes (75%)
and <3 em in size.
+ DIAGNOSIS: Arteriovenous malformation.
+ KEY FACTS
CLINICAL
• Ten percent of cases are identified in infancy or childhood,
although the vast majority are not recognized
until the third and fourth decade of life .
• They are twice a s frequent in women a s in men.
• Patients commonly present with hemoptysis or
dyspnea on exertion or occasionally with cerebral
embolism.
• Of all pulmonary AVMs, 40% to 65% are associated
with Osler-Weber-Rendu disease ( hereditary hemorrhagic
telangiectasia) . This is an autosomal dominant
disorder that manifests clinically in adult life . Many of
these patients have arteriovenous communications
elsewhere, including the skin, mucous membranes,
and other organs.
43
RADIOLOGIC
• The typical finding is a round, lobulated, well-defined
mass, most often in the medial third of the lung.
• About 33% of cases will have multiple pulmonary AVMs.
• The size of the AVMs is less than one to several centimeters
in diameter.
• The feeding artery and draining vein are often
enlarged and identifiable on the chest radiograph.
• The vascular nature of the radiographic opacities can be
demonstrated by an increase in size during a Mueller
maneuver and a decrease during a Valsalva maneuver.
• A change in size may also be visible when erect (smaller)
and supine (larger) radiographs are compared.
• Pulmonary angiography remains the standard imaging
technique and is performed to confirm the presence of
pulmonary AVMs, detect synchronous malformations,
and delineate the anatomy of the feeding and draining
vessels.
• CT is a sensitive, noninvasive means of establishing the
diagnosis and eliminates the need for angiography
when treatment is not being contemplated.
• Embolization is now the preferred treatment for this
condition and is performed with detachable balloons
or steel coils.
+ SUGGESTED READING
Allison DJ, Pinet F, Allison HJ. Interventional Techniques in the
Thorax. In EJ Potchen, RG Grainger, R Greens (eds),
Pulmonary Radiology-By Members of The F1eischner Society.
Philadelphia: Saunders, 1 99 3;340-360.
Fraser RG, Pare JAP, Pare PD, et a1. Diagnosis of Diseases of the
Chest ( 3rd ed). Philadelphia: Saunders, 1 9 9 1 ;882-939.
Remy-Jardin M, WattirUle L, Deffontaines C. Pulmonary arteriovenous
malformations: Evaluation with CT of the chest before and
after treatment. Radiology 1 992;182:809-8 1 6 .

Front 22

A 60-year-old man who is a foundry worker presents with progressive dyspnea.

Back 22

DIFFERENTIAL DIAGNOSIS
• Silicosis: This is the best diagnosis given the eggshell
calcifications and conglomerate masses. Coal worker's
pneumoconiosis is indistinguishable radiographically
from silicosis and should be included in the differential
diagnosis .
• Sarcoidosis: Both eggshell calcifications and conglomerate
masses can also be seen in sarcoidosis. However,
the symmetry and sharp lateral borders of the opacities,
along with the clinical history, makes silicosis
more likely.
• Tuberculosis (TB)/histoplasmosis: Eggshell calcifications
and conglomerate masses can result from pulmonary
infection by TB or histoplasmosis. However, the
symmetry and sharp lateral borders of the opacities,
along with the clinical history, makes silicosis more likely.
• Lymphoma: Treated lymphoma can result in eggshell
calcification of hilar or mediastinal nodes. The
parenchymal findings and clinical history make silicosis
more likely.
+DIAGNOSIS: Silicosis with conglomerate masses.
+ KEY FACTS
CLINICAL
• Silicosis is a chronic, nodular, and fibrotic disease
caused by long-term exposure to silica.
• Typical occupational histories include hard-rock mining,
foundry work, and sandblasting.
• Clinical symptoms and radiographic findings usually
require 1 0 to 20 years of exposure.
• There is an acute form known as acute silicoproteinosis.
It is associated with heavy exposure and can
occur over a period of several months. Its clinical and
radiographic course resembles alveolar proteinosis.
45
• Silicosis increases the risk of TB , particularly in patients
with conglomerate masses. Culture of the organism is
difficult in these patients.
RADIOLOGIC
• Simple silicosis is characterized by multiple 1 - to 1 0-
mm nodules that predominate in the upper lobes; 20%
of nodules calcify.
• Complicated silicosis is characterized by coalescence of
the nodules into conglomerate masses >1 cm in diameter.
These masses can reach 10 cm in size and typically
migrate toward the hila with time. Paracicatricial
emphysema is common.
• The conglomerate masses can cavitate due to ischemic
necrosis. Development of TB in these cavities (silicotuberculosis)
is common. Other signs of TB in patients
with silicosis include apical pleural thickening and
rapid progression of nodules.
• Caplan's syndrome ( cavitary rheumatoid nodules in
patients with coal worker's pneumoconiosis) can closely
resemble complicated silicosis.
• CT is superior to plain chest radiographs in the detection
of early silicosis and in identifying other conditions
that cause dyspnea, such as emphysema. It can
also be key for the diagnosis of superimposed TB and
lung cancer.
+ SUGGESTED READING
Begin R, Bergeron D, Samson L, et al. CT assessment of silicosis in
exposed workers. AJR Am J Roentgenol 1 987;148:509-5 14.
Dee P, Suratt P, Winn W. The radiographic findings in acute silicosis.
Radiology 1978;1 26;359-363.
McLoud TC, Gamsu G. Pneumoconiosis: Radiology and HighResolution
Computed Tomography. In EJ Potchen, RG
Grainger, R Greene (eds), Pulmonary Radiology. Philadelphia:
Saunders, 1 993;81-93.

Front 23

A 23-year-old man presents with an acute onset of productive cough, fever, and
chills. The patient is otherwise healthy and has no prior illnesses.

Back 23

DIFFERENTIAL DIAGNOSIS
• Community-acquired bacterial pneumonia: The
acute onset of symptoms and the radiographic findings
suggest a community-acquired pneumonia such as that
caused by Streptococcus pneumoniae or Haemophilus
injluenzae.
• Pneumonia due to other organisms: Less common
causes of pneumonia that can mimic the more common
bacterial varieties include primary tuberculosis
(TB ) , Legionnaires' pneumonia, actinomycosis, and
coccidioidomycosis or blastomycosis pneumonias in
endemic regions.
• Noninfectious entities: Pulmonary embolism,
eosinophilic pneumonia, contusion or hemorrhage,
and bronchitis obliterans organizing pneumonia
( BOOP) should also be considered as they can manifest
with peripheral consolidation.
+ DIAGNOSIS: Pneumococcal pneumonia.
+ KEY FACTS
CLINICAL
• The diagnosis of community-acquired pneumonia may
be difficult since the pathogens are not identified in as
many as 50% of patients. Nevertheless, S. pneumoniae
is the most frequent cause. Other pathogens include
Mycoplasma pneumoniae, respiratory viruses,
Chlamydia pneumonia, and Haemophilus injluenzae.
• S. pneumoniae can occur in healthy people but is frequently
found in non critically ill patients who require
hospitalization . These patients are usually >65 years of
age or have coexisting illness such as diabetes mellitus,
chronic renal failure, congestive heart failure, or
chronic obstructive pulmonary disease.
• Mortality rates range from 5% to 2 5%, with death usually
occurring in the first 7 days of hospitalization .
• Severe pneumonia with mortality rates as high as 50%
is recognized when certain conditions exist. These
conditions include a respiratory rate >30, low urine
47
output, shock, or chest radiographs revealing multiple
lobe involvement or significant increase in opacity
within 2 days of admission.
• While S. pneumoniae is particularly sensitive to penicillin,
some clinicians direct therapy at a broader group
of organisms and may include antibiotics such as erythromycin,
third-generation cephalosporins, or
trimethaprim-sulfamethoxazole. Many recommend
immunization with pneumococcal vaccines.
RADIOLOGIC
• Pneumococcal pneumonia usually manifests as a homogeneous
parenchymal opacity that begins at the periphery
and spreads to involve the entire segment or lobe.
• Air bronchograms are common.
• Lymphadenopathy is rare; cavitation occurs with some
serotypes of S. pneumoniae.
• Pleural fluid or parapneumonic effusions can be seen
in as many as 50% of patients.
• With appropriate antibiotic therapy, some radiologic
evidence of improvement is usually seen within a few
days, and complete resolution may be seen in approximately
2 weeks. In some cases, complete resolution
requires up to 6 weeks.
• Failure of clinical or radiographic response to ordinary
antibiotics should suggest the possibility of another
infectious agent, an obstructing lesion, or an insensitive
organism.
+ SUGGESTED READING
Chien S, Pichotta P, Seipman N, Chan CK. Treatment of community-
acquired pneumonia. Chest 1993;103:697-70 l .
Frame PT. Acute infectious pneumonia in the adult. ATS News
1982; 1 8-25.
iederman MS, Bass JB Jr, Campbell GD, et al. Guidelines for the
initial management of adults with community-acquired pneumonia:
Diagnosis, assessment of severity, and initial antimicrobial
therapy. Am Rev Respir Dis 1993; 148 : 1 4 1 8-1426.
Ostergaard L, Andersen PL. Etiology of community-acquired pneumonia.
Chest 1993 ; 1 04 : 1400-1407.

Front 24

A 25-year-old woman presents with pleuritic chest pain, high fever, nonproductive
cough, and a history of intravenous drug abuse

Back 24

DIFFERENTIAL DIAGNOSIS
• Eosinophilic pneumonia-chronic eosinophilic
pneumonia (EP-CEP): This disorder typically manifests
with bilateral peripheral opacities as in this case.
However, cavitation is rarely, if ever, seen in
eosinophilic pneumonia.
• Bacterial pneumonia: Bacterial pneumonia usually
begins in the periphery of the lung and can be multilobar.
However, the symmetry shown in this case is
unusual for this diagnosis.
• Pulmonary infarction: Pulmonary infarcts can manifest
as peripheral consolidation ( Hampton's hump ) .
However, multifocal pulmonary cavitation i s not a typical
feature of pulmonary embolism with infarction.
• Septic pulmonary embolism: Septic emboli usually
manifest as peripheral, poorly defined nodular opacities.
In severe cases, the nodules can coalesce into
larger areas of consolidation. Cavitation is common.
• Bronchitis obliterans organizing pneumonia
(BOOP): Although BOOP usually manifests with scattered
peripheral consolidation, cavitation virtually
excludes this diagnosis.
• Trauma: Pulmonary contusion or hemorrhage often
occurs in the lung periphery, and lung cysts or cavitation
can also occur after thoracic trauma. However, the
number of lesions seen in this case makes this diagnosis
less likely.
• Metastatic disease: Multiple cavities can result from
metastatic disease to the lung, particularly from squamous
cell carcinomas. Metastases are generally discreet
and do not coalesce, as seen in this case.
• Collagen vascular disease: Entities such as Wegener's
granulomatosis and rheumatoid lung disease can result
in cavitary nodules, but the number and close proximity
of the cavities to one another, as seen in this case,
are not typical features of these disorders.
+ DIAGNOSIS: Septic emboli.
+ KEY FACTS
CLINICAL
• Septic pulmonary emboli usually result from tricuspid
valve endocarditis due to intravenous drug abuse, head
49
and neck infections with pharyngeal or internal jugular
vein phlebitis, or phlebitis from an indwelling catheter
or an infected arteriovenous fistula.
• Symptoms include high fever, cough, dyspnea, chest
pain, and occasional hemoptysis.
• Typical organisms include Staphylococcus aureus and
anaerobes.
• Antibiotic therapy is usually successful, although clinical
improvement can take several weeks.
RADIOLOGIC
• Septic emboli manifest as poorly defined nodules ( usually
1 to 2 cm in diameter) in the lung periphery. They
are usually more numerous in cases of tricuspid endocarditis
than from other sources.
• In the first few days after initiation of therapy, new
nodules may appear.
• Cavitation is seen in approximately 50% of nodules.
The walls are moderately thick and irregular.
• Healing of these nodules or cavities is noted by a
decrease in size and eventual resolution. Occasionally,
a peripheral linear scar remains.
• Hilar and mediastinal lymphadenopathy has been
reported rarely.
• Pleural effusion(s) are not uncommon.
• CT is generally not indicated but, as in other situations,
can reveal a greater extent of involvement than
chest radiographs. On CT, a vessel leading into the
nodule is a suggestive, but nonspecific, finding.
+ SUGGESTED READING
Gumbs RV, McCauley Dr. Hilar and mediastinal adenopathy in septic
pulmonary embolic disease. Radiology 1 98 2 ; 1 42 : 3 1 3-3 1 5 .
Hadlock FP, Wallace RJ Jr, Rivera M . Pulmonary septic emboli secondary
to parapharyngeal abscess: Postanginal sepsis. Radiology
1979 ; 1 30:29-33 .
Jaffe RB, Koschmann EB. Septic pulmonary emboli. Radiology
1 970;96 :527-532.
Kuhlman JE, Fishman EK, Teigen C. Pulmonary septic emboli:
Diagnosis with CT. Radiology 1 990; 1 74:2 1 1-2 1 3 .

Front 25

A 2 1 -year-old man presents with fever, cough, and dyspnea. On physical examination,
a severe vesicular skin rash is discovered.

Back 25

DIFFERENTIAL DIAGNOSIS
• Primary lung neoplasm: Multiple, poorly defined
nodules can be seen in both bronchoalveolar cell carcinoma
and lymphoma. With alveolar cell carcinoma and
lymphoma, larger areas of consolidation are frequently
seen. Witl1 lymphoma, lymphadenopathy and pleural
fluid are frequent.
• Kaposi's sarcoma: The poorly defined nodules of
Kaposi's sarcoma are generally less numerous and larger
tl1an those seen in this case.
• Metastases: Metastatic disease from a variety of primary
sources could account for this radiographic pattern.
• Disseminated fungal infection: In disseminated fungal
infection, the nodules are usually more discrete
than seen in this case. However, in cases of overwhelming
infection, the nodules can sometimes be
poorly defined and coalescent. Severe primary histoplasmosis
can also manifest with multiple, poorly
defined nodules, but the degree of coalescence noted
in this case is unusual.
• Miliary tuberculosis: This is unlikely because the size
of nodules in this case is larger than the usual 1 - to 3-
mm opacities seen in classic miliary infections.
• Collagen vascular disease: Entities such as Wegener's
granulomatosis and rheumatoid lung disease can manifest
with multiple nodules, but generally they are larger,
less numerous, and more discrete than the ones
noted in this case. Cavitation is frequently seen in
these entities.
• Varicella pneunlOnia: The vesicular skin rash associated
witl1 diffuse poorly defined pulmonary nodules and
lymphadenopathy make this the most likely diagnosis.
DIAGNOSIS: Varicella pneumonia.
KEY FACTS
CLINICAL
• Pneumonia usually develops 2 to 3 days after the
appearance of the vesicular eruption. The incubation
time postexposure is 3 to 2 1 days.
• The rash is particularly severe at the onset of pneumonia.
• Presenting symptoms include cough, dyspnea, hemoptysis,
tachypnea, chest pain, and high fever.
51
• Pneumonia without fever or new skin lesions is rare.
• The incidence of pneumonia ranges from 1 0% to 50%,
with a greater frequency in cigarette smokers.
• Twenty-five percent of the fatalities related to varicella
pneumonia occur in adults, although only 2% of the 3
to 4 million annual cases of varicella occur in adults.
• Untreated adult varicella pneumonia has a 1 0% fatality
rate; a fatality rate of 40% is seen in pregnant or postpartum
women and in cancer and bone marrow transplant
patients. Therapy with acylovir may be effective
in shortening the course of cutaneous disease, as well
as in preventing pneumonia. Patients treated with acyclovir
also have a lower mortality rate .
• Varicella vaccines may provide protection in approximately
70% of adults and 90% of children.
RADIOLOGIC
• Varicella pneumonia typically manifests with poorly
defined nodular opacities tl1at are distributed diffusely
throughout both lungs. The nodules are usually 5 to
1 0 mm in diameter. Coalescence is frequent as the
nodules enlarge.
• Hilar lymph node enlargement may be seen in some
cases. The nodes do not usually calcify.
• Resolution occurs in 3 to 5 days in mild cases; however,
radiographic abnormalities can persist for weeks in
severe disease .
• Healing can result in small calcific opacities throughout
the lungs. These are usually smaller and less uniform
than the calcifications seen with prior histoplasmosis.
Less than 2% of affected patients have residual
pulmonary calcification .
• Pleural effusions are rare .
• SUGGESTED READING
Feldman S. Varicella-zoster virus pneumonitis. Chest 1994;
1 06:225-275.
Fraser RG, Pare JAP, Pare PD, et aL Diagnosis of Diseases of the
Chest. Philadelphia: Saunders, 1 989;1 062-1068.
Sargent EN, Carson MJ, Reilly ED. Roentgenographic manifestations
of varicella pneumonia with posunortem correlation.
Radiology 1 966;98 :305-3 1 7.

Front 26

A 47-year-old man presents with a 3-week history of low-grade fevers, night sweats,
and a l O-pound weight loss. The patient is an alcoholic. Periodontal disease is
observed on physical examination

Back 26

DIFFERENTIAL DIAGNOSIS
• Postprimary tuberculosis (TB): Postprimary TB usually
manifests as cavitary disease in the superior segment
of the lower lobe or the posterior segment of the
upper lobe.
• Bronchogenic carcinoma: A cavitating neoplasm such
as squamous cell carcinoma should be considered but
is less likely due to the extent of the consolidation and
multifocal cavitation.
• Trauma: Pulmonary contusion with traumatic lung
cysts would also be a consideration in the proper clinical
setting.
• Pneumonia with lung abscess: Pneumonias due to
Klebsiella pneumoniae, other gram-negative organisms,
or certain serotypes of Streptococcus pneumoniae
can result in necrosis and abscess formation. The
indolent clinical symptoms, however, do not favor
these diagnoses.
• Anaerobic pneumonia: These usually occur in the
dependent portions of the lungs following aspiration
and may pursue an indolent clinical course, as in this
case. Cavitation is common.
+ DIAGNOSIS: Anaerobic pneumonia from aspiration.
+ KEY FACTS
CLINICAL
• Patients with a history of unconsciousness, alcoholism,
seizure disorder, severe trauma, or recent anesthesia
are at risk for aspiration and anaerobic pneumonia.
• Clinical features of fever, cough, and white blood cell
count elevation can be seen within 12 hours after aspiration
but are more typical in the first 48 hours.
• Symptoms can be minimal, with a more indolent
course of nonproductive cough, low-grade fever, and
weight loss. With cavitation, expectoration increases
and hemoptysis can occur.
53
• Periodontal disease may be observed, although this is not
necessary as poor endobronchial clearance alone may
contribute to the development of anaerobic infection.
• The foul odor of anaerobic bacteria is fairly specific
and can suggest the diagnosis.
RADIOLOGIC
• Aspiration pneumonia occurs almost exclusively in the
superior segment of the lower lobes, posterior segment
of the upper lobes, and posterior basal segment of the
lower lobes. The remainder of the upper lobes, the lingula,
and the right middle lobe are rarely involved.
• Initially, a heterogeneous opacity is noted within 2
days of aspiration. Within a week, more homogeneous
consolidation develops, sometimes with cavitation.
• Over the next few weeks, chronic low-grade infection
can develop and manifest as a thick-walled cavity. At
this point, the clinical features and radiographic appearance
can mimic postprimary TB.
• Air-fluid levels are common.
• Associated empyema is common. Approximately 50%
of patients have pleural fluid alone or in combination
with lung disease.
• Lymphadenopathy is uncommon.
• Healing of large abscess cavities is slow and is recognized
by a decrease in the diameter of the cavity. The
size of the air-fluid level within the cavity reflects the
patency of communication with an airway and does not
correlate with either clinical worsening or improvement.
+ SUGGESTED READING
Bartlett JG. Anaerobic bacterial pneumonitis. Am Rev Respir Dis
1 979; 1 1 9 : 1 9-2 3 .
Bartlett JG. Anaerobic bacterial infections o f the lung. Chest
1 987;9 1 :90 1-909.
Landay MJ, Christensen EE, Bynum LJ, Goodman Pc. Anaerobic
pleural and pulmonary infections. AJR Am J Roentgenol
1 980;1 34:233-240.

Front 27

A 54-year-old man was hospitalized for an orthopedic surgical procedure. The preoperative
chest ftlm was normal. Two days into hospitalization, the patient developed
a fever, cough, and elevated white blood cell count. His chest ftlm abnormalities and
clinical symptoms were similar to those seen in four other patients in the hospital
within a period of 3 weeks.

Back 27

DIFFERENTIAL DIAGNOSIS
• Neoplasm: eoplasm is unlikely given the rapid onset
of symptoms and radiographic appearance of the lungs.
• Gram-negative pneumonia: Pneumonia caused by
nosocomial gram-negative organisms should be considered
. However, the homogeneity of this opacity and
the mass-like appearance are somewhat peculiar. Gramnegative
organisms hematogenously disseminated tend
to cause more peripheral amorphous and heterogeneous
opacity. They also have a strong tendency to
cavitate and may induce a parapneumonic effusion.
• Community-acquired pneumonia: The coincidental
development of community-acquired pneumonia such
as pneumococcal pneumonia should be considered. If
there is a failure to respond to ordinary antibiotics,
however, other considerations need to be raised. Among
these are the possibility of primary TB, fungal infections
such as blastomycosis or coccidioidomycosis, or unusual
organisms such as nocardia or actinomycosis.
• Legionella pneumonia: The outbreak of similar cases
in other patients in the hospital supports a diagnosis of
hospital contamination with Legionella pneumophila.
+ DIAGNOSIS: Legionnaires' disease.
+ KEY FACTS
CLINICAL
• Legionnaires' disease is caused by L. pneumophila, a
pleomorphic gram-negative bacillus recognized in
1 976 during an outbreak in Philadelphia. Other epidemics
have occurred in nursing homes and hospitals
and generally arise from contaminated water sources.
• Patients usually present with gradual onset of fever,
chills, cough, and dyspnea. Headaches, gastrointestinal
symptoms, and pleuritic pain have also been reported.
Hyponatremia is more frequent in early legionellosis
than in other pneumonias.
55
• Direct fluorescent antibody staining of SpUtun1 provides
rapid diagnosis but is less sensitive than culture.
• Treatment with erythromycin generally results in a
successful outcome.
RADIOLOGIC
• Legionnaires' disease usually begins with a focal area of
homogeneous opacity that may manifest as a large,
poorly marginated mass.
• Progression to bilateral lung involvement occurs in
70% of patients, typically within the first few days.
Progression of radiographic findings is rapid and may
continue after institution of therapy.
• Lymphadenopathy is rare. Pleural fluid has been reported
in 30% to 60% of patients with Legionnaires' disease.
• Cavitation is uncommon but has been reported primarily
in patients who are immunosuppressed .
• Resolution is usually rapid but on occasion is quite
prolonged.
+ SUGGESTED READING
Dietrich PA, Johnson RD, Fairbank JT, Walke JS. The chest radiograph
in Legionnaires' disease. Radiology 1 978 ; 1 27:577-582.
Edelstein PH. Legionnaires' disease. Clin I nfect Dis 1993; 16:74 1-749.
MacFarlane JT, Miller AC, Smith WHR, et al. Comparative radiographic
features of community acquired Legionnaires' djsease,
pneumococcal pneumorna, mycoplasma pneumonja, and psittacosis.
Thorax 1 994;39:28-3 3.
Meenhorst PL, Mulder JD. The chest X-ray in LegioneUa pneumorna
( Legionnaires' disease ). Eur J RadioI 1983;3 : 1 80- 1 86.
Moore EH, Webb WR., Gamsu G, Golden JA. Legionnaires' disease
in the renal transplant patient: Clinical presentation and radiographic
progression. Radiology 1 984; 1 5 3 :589-593.
Roig J, Dontingo C, Morera J . Legionnaires' rusease. Chest
1 994; 1 0 5 : 1 8 1 7-1825

Front 28

A 32-year-old homosexual man who tested positive for the human immunodeficiency
virus (HIV) 3 years earlier now presents with gradual onset of shortness of
breath and slight fever.

Back 28

DIFFERENTIAL DIAGNOSIS
• Bronchiectasis: The size and type of cavitation is
occasionally seen in severe bronchiectasis, although
there is no other evidence of peribronchial thickening
nor is there a history of a chronic productive cough.
• Pneumatoceles: Those due to trauma, staphylococcal
pneumonia, or hydrocarbon inhalation are usually
localized to a single lobe rather than disseminated
throughout the lungs. However, pneumatoceles due to
Pneumocyrtis carinii pneumonia can be diffuse.
• Coccidioidomycosis: Chronic coccidioidomycosis can
result in thin-walled cavities, but the extent of involvement
in this patient is unusual for coccidioidomycosis,
particularly given the mild symptoms.
• Cavitary metastases: Although cavitary metastases can
be this thin-walled, there is usually more irregularity to
the walls. Also, the presence of non cavitary nodules
would have been more suggestive of this diagnosis.
• Collagen vascular disease: Wegener's granulomatosis
and rheumatoid lung disease can manifest with cavitary
nodules/masses. However, the walls are generally not
this thin, nor are the nodules this numerous.
+ DIAGNOSIS: Pneumocystis carinii pneumonia
with pneumatoceles.
+ KEY FACTS
CLINICAL
• P carinii was initially considered a trypanosome, was
then reclassified as a protozoan, but is phylogenetically
more closely related to fungi .
• In the United States, asymptomatic infection with P
carinii occurs mainly in early childhood. Clinically
identifiable disease manifests in severely immunocompromised
patients.
• Symptoms are generally nonspecific, including fever,
dyspnea, nonproductive cough, fatigue, and weight loss.
• Prophylaxis with aerosolized pentamidine or periodic
trimethoprim-sulfamethoxasole therapy has been effective
in decreasing the number of patients presenting
with P carinii pneumonia.
• The diagnosis is made by observing organisms on
induced sputum, bronchoalveolar lavage, or transbronchial
lung biopsy specimens.
57
• Treatment is generally with trimethoprim-sulfamethoxazole
or pentamidine. Steroids, dapsone, or clindamycin-
primaquine have also been used.
• Response to therapy is generally excellent. Clinical
improvement is typically seen within several days.
Nevertheless, some patients will procede to respiratory
failure, requiring stringent therapeutic supportive
measures.
• Pneumatoceles observed in PCP are the result of the
organism and not a result of aerosolized pentamidine
therapy.
RADIOLOGIC
• PCP typically manifests with diffuse, bilateral, fine to
medium reticulonodular opacities.
• Unusual appearances include focal homogeneous
opacities and larger ( 1 to 2 cm ) nodules with or without
cavitation.
• Pneumatoceles are seen in approximately 1 0% of
patients with PCP. Although their size may fluctuate
daily, pneumatoceles are usually stable for several days
to weeks. They typically resolve within 6 months. Fluid
levels in pneumatoceles are extremely rare. Spontaneous
pneumothorax occurs in 5% to 6% of patients
with PCP.
• Lymphadenopathy and pleural effusions are extremely
rare in patients with PCP.
• With appropriate therapy, resolution of abnormalities
can be complete after 1 0 days. Occasionally, residual
fibrosis is observed.
+ SUGGESTED READING
Goodman PC, Daley C, Minagi H. Spontaneous pneumothorax in
AIDS patients with Pneumocystis carinii pneumonia. AJR Am J
Roentgenol 1985;147:29-3 l .
Goodman PC. AIDS. I n 1 M Freundlich, DG Bragg (eds), A
Radiologic Approach to Diseases of the Chest. Baltimore:
Williams & Wilkins, 1 992.
Hopewell PC, Masur H . Pnemnocystis carinii Pneumonia: Current
Concepts. In MA Sande, PA Volberding (eds), The Medical
Management of AIDS (4th ed). Philadelphia: Saunders, 1 99 5 .
Sandhu J S , Goodman P C . Pulmonary cysts associated with
Pneltmocystis cari��ii pneumonia in patients with AIDS.
Radiology 1 989; 1 73: 33-35

Front 29

Screening manunogram in a 44-year-old woman

Back 29

DIFFERENTIAL DIAGNOSIS
• Milk of calcium: This is the best diagnosis because
milk of calcium has different appearances depending
on the mammographic projection obtained. The calcifications
are often smudge-Like or indistinct on the
craniocaudal views but have a teacup or meniscus
appearance on horizontal beam radiographs.
• Fat necrosis: The calcifications associated with fat
necrosis often vary in density and shape and can be
indistinguishable from carcinoma. Many of the calcifications
evolve over time to a more coarse configuration,
or may have an eggshell appearance, as seen in oil
cysts. However, the appearance of fat necrosis does not
usually vary on the different projections, making this
an unlikely diagnosis in this case.
+ DIAGNOSIS: Milk of calcium.
+ KEY FACTS
CLINICAL
• Milk of calcium represents calcified debris that is sedimented
in the dependent portions of microcysts or
cystically dilated acini of cystic lobular hyperplasia.
• Benign milk of calcium calcifications are seen in 4% to
6% of women undergoing mammography.
• Milk of calcium is usually seen in multiple areas of the
breast and is usually bilateral. It can be a diagnostic
problem when it appears as a unilateral focus. It is
important to recognize milk of calcium so that an
inappropriate biopsy is not recommended.
• Milk of calcium calcifications are benign and do not
require a biopsy, but carcinomas can occur adjacent to
such microcystic calcifications. Therefore, each group
of calcifications must be inspected carefully.
RADIOLOGIC
• The shape of milk of calcium calcifications has been
described as meniscus, crescent, teacup, or semilunar.
61
The meniscus or crescent shape is best seen on an
erect 90-degree lateral projection since the x-ray beam
is horizontal and therefore tangential to the fluid calcium
interface in the microcyst.
• On the 90-degree lateral view, the tops of the calcifications
will be oriented parallel to one another along the
horizontal axis. The upper border of the calcification
may be less distinct than the lower border where the
sedimented calcified debris is sharply bounded by the
wall of the microcyst.
• The characteristic meniscus or crescent shape is not as
well seen on the 45-degree mediolateral oblique view.
• On the craniocaudal projection, the calcifications are
seen en face since the x-ray beam is vertical and therefore
perpendicular to the fluid calcium interface in the
microcyst.
• On the craniocaudal projection, the calcifications are
amorphous, round, or ovoid smudges. They can be so
faint that they are invisible.
• The dramatic difference in the appearance of the calcifications
on the craniocaudal, mediolateral, and 90-
degree lateral projections is a characteristic feature of
benign milk of calcium.
• When milk of calcium calcifications are suspected, a
magnification view in the 90-degree lateral projection
should be performed.
SUGGESTED READING
Hamer MJ, Cooper AG, Pile-Spellman ER. Milk of calcium in breast
microcysts: Manifestation as a solitary focal disease. AJR Am J
Roentgenol 1 988;1 50:789 .
Linden SS, Sickles EA. Sedimented calcium in benign breast cysts.
AJR Am J Roentgenol 1 989; 1 52 :957.
Sickles EA, Abele JS. Milk of calcium within tiny benign breast cysts.
Radiology 1 98 1 ; 1 4 1 :65 5 .

Front 30

A 45-year-old asymptomatic woman presenting fQr a screening mammogram.
A breast ultrasound was subsequently performed

Back 30

DIFFERENTIAL DIAGNOSIS
• Cysts: As seen in this case, cysts are anechoic, wellcircumscribed
masses that have posterior acoustic
enhancement. Cysts are the most commonly encountered
breast masses, which cannot be differentiated
from other circumscribed masses at mammography
unless they contain milk of calcium. Sonography can
differentiate cysts from solid breast masses accurately.
• Fibroadenomas: Fibroadenomas can be multiple or
bilateral in 1 5% of cases and are the most common palpable
breast masses in adolescents and young women.
Although noncalcified fibroadenomas cannot be differentiated
at mammography from other circumscribed
masses, fibroadenomas appear solid at sonography,
unlike the lesions in this case. Large, coarse, popcornlike
calcifications are pathognomonic mammographic
findings of degenerating fibroadenomas.
• Metastases: The sonographic appearance of metastases
is that of a solid mass, differing from the lesions seen
in this case. Metastatic disease to the breast from an
extramammary primary malignancy is rare ( 0 . 5% to
1 .3% of breast malignancies) and most often has the
mammographic appearance of single or multiple circumscribed
masses. A clinical history of extramammary
malignancy should be present to suspect this diagnosis.
• Papillomas: Papillomas are rarely visible at mammography.
They are usually d cm in size and are typically
located in the subareolar region. At sonography, papillomas
are often solid, lobulated masses. These features
make this diagnosis unlikely in the case illustrated. A
papilloma can also present as a solid nodule within a
cyst, for which biopsy is indicated to exclude a malignant
lesion.
• Lymph nodes: I ntramammary lymph nodes are typically
d cm in size, often demonstrate a fatty hilus at
mammography, and are usually located in the upper
outer quadrants of the breasts. At sonography, lymph
nodes are usually hypoechoic with an echogenic fatty
hilus. All these features make this an unlikely diagnosis
in this case.
+ DIAGNOSIS: Bilateral simple cysts confirmed by
ultrasound.
+ KEY FACTS
CLINICAL
63
• Cysts can be seen in all age groups but are more common
in women 30 to 50 years of age.
• Cysts arise in the terminal-duct lobular units. They can
be grossly visible at mammography or seen only microscopically.
• Autopsy studies report grossly visible cysts in 20% to
50% of women.
• Cysts cannot be differentiated reliably from solid palpable
masses on physical examination. Therefore,
sonography or needle aspiration is necessary to confirm
the diagnosis.
RADIOLOGIC
• Cysts are typically round, oval, or lobular in shape and
often multiple and bilateral.
• Cyst margins are usually well defined on mammography
if not obscured by adjacent fibroglandular tissue.
Occasionally, the margins can be indistinct.
• Because cysts GUillot be differentiated from other circumscribed
masses at mammography, sonography is
often performed to establish the diagnosis.
• Strict sonographic criteria for a simple cyst include
anechoic appearance, smooth, well-defined margins,
and posterior acoustic enhancement.
• When multiple, bilateral, well-circumscribed masses are
present on a baseline screening mammogram, sonography
can be performed to determine if the masses are
cystic or solid. A 1 2-month follow-up mammogram is
usually recommended for cystic or solid masses if there
are no suspicious features, dominant mass, or history
of an extramammary malignancy.
+ SUGGESTED READING
Adler DD. Mammographic Evaluation of Masses. In DB Kopans
(ed ), Syllabus: A Categorical Course in Breast I maging. Oak
Brook, IL: RSNA, 1 99 5 ; 1 0 7-1 1 6 .
Bohman L G , Bassett LW, Gold RH, Volt R . Breast metastases from
extramammary malignancies. Radiology 1982;1 44:309-3 1 2 .
Jackson VP. Circumscribed Microlobulated Noncalcified Mass. I n
BA Siegel ( e d ) , Breast Disease Test a n d SyUabus ( 2 n d series).
Reston, VA: American College of Radiology, 1993 ;89-99.
Kopans DB (ed). Breast Imaging. Philad

Front 31

Screening mammogram in a 63-year-old woman.

Back 31

DIFFERENTIAL DIAGNOSIS
• Sternalis muscle: This is the typical mammographic
appearance and correct anatomic location for the sternalis
muscle, making tillS the best diagnosis.
• Fibroadenoma: Fibroadenomas result from stromal
overgrowth of the lobules and are typically seen more
anteriorly in the breast. The inability to image the
lesion on the mediolateral oblique view makes t1Us
diagnosis less likely.
• Carcinoma: Because carcinomas can occur at any location
in the breast, tillS diagnosis was considered and
prompted biopsy in t1Us case.
+ DIAGNOSIS: Sternalis muscle.
+ KEY FACTS
CLINICAL
• The sternalis muscle is a normal variant of chest wall
musculature.
• It lies anterior to the pectoralis muscle along the edge
of the sternum, extending from the inferior clavicle to
the caudal sternum.
• TillS muscle is uncommon, occurring in 8% of men and
women, and occurs unilaterally twice as often as bilaterally.
65
RADIOLOGIC
• The sternalis muscle appears as a small asymmetric
density of varying shapes that projects into the medial
breast posteriorly.
• The sternalis muscle should be differentiated from the
pectoralis muscle, which is seen as a long convex bulge
along the chest wall on 30% of craniocaudal mammogran1S.
• The sternalis muscle is seen on the craniocaudal mammogram
only and not on tl1e mediolateral oblique
mammogram.
• In the case illustrated here, the mass could not be
localized in two views; therefore needle localization
was performed using stereotactic guidance.
• Awareness of t1Us entity prevents needless biopsies. If
necessary, t1Us finding can be confirmed to be sternalis
muscle using CT or MRl.
SUGGESTED READING
Bradley FM, Hoover HC, Hulka CA, et al. The sternalis muscle: An
unusual normal finding seen on mammography. AJR Anl J
Roentgenol 1996; 1 66:33-36.
Kopans DB. Pathologic, Mammographic, and SOLlographic
Correlation. In DB Kopans (ed), Breast I maging. Philadelphia:
Lippincott, 1 9 89;262-265.

Front 32

Screening mammogram in a 73-year-old woman. Past medical history is significant
for abdominal surgery 1 year ago with chronic wound dehiscence

Back 32

DIFFERENTIAL DIAGNOSIS
• Metastatic breast carcinoma: This diagnosis is considered
unlikely because no evidence for primary breast
carcinoma is seen within the fatty replaced breast.
• Metastasis from an extramammary carcinoma: I f
the patient's abdominal surgery was for resection of
ovarian or colon carcinoma, the diagnosis of metastatic
carcinoma should be considered, although metastases
to the breast are very rare . Without a history of metastases
elsewhere from an extramammary primary, this
diagnosis should be considered very unlikely.
• Reactive lymph node: In a patient with the clinical
history of chronic abdominal wound infection, a reactive
intramammary lymph node should be considered
likely if no other abnormalities are identified throughout
d1e ipsilateral breast.
DIAGNOSIS: Reactive enlargement of an
intramammary lymph node.
KEY FACTS
CLINICAL
• Intramammary lymph nodes can enlarge secondary to
infections located on d1e chest, in d1e breast, in the
abdomen and upper extremity, or due to dermatologic
abnormalities such as psoriasis.
67
• Physical examination to search for inciting infectious
or dermatologic abnormalities is essential in correcdy
diagnosing correcdy reactive lymph nodes within the
breast.
RADIOLOGIC
• Magnification views are often lIseful in evaluating a
suspected intramammary lymph node because they
may better demonstrate the fatty hilum.
• The management of enlarged intramammary lymph
nodes that occur without other mammographic abnormality
requires mammographic foUow-up after treatment
of the infectious or dermatologic abnormality to
assure that the lymph node returns to normal size and
density.
• SUGGESTED READING
Kopans DB. Mammography. In DB Kopans (ed), Breast Imaging.
Philadelphia: Lippincott, 1 989;34-226.
Kopans DB, Meyer JE. Benign lymph nodes associated with dermatitis
presenting as breast masses. Radiology 1 980; 1 37: 1 5- 1 9 .
Lindfors KK, Kopans D B , McCarthy KA , e t a 1 . Breast metastasis to
intra mammary lymph nodes. AJR Am J Roentgenol 1986;146:
1 33- 1 36.
Meyers JE, Kopans DB, Lawrence WD. Normal intramammary
lymph nodes presenting as occult breast masses. Breast
1 982;8:30-32.
Svane G, Franzen S. Radiologic appearance of nonpalpable intramammary
lymph nodes. Acta Radiol 1 993;34:577-580.

Front 33

A 43-year-old woman with a palpable lump in the upper outer quadrant of the right
breast presents for diagnostic mammography. There is no past surgical history.

Back 33

DIFFERENTIAL DIAGNOSIS
• Carcinoma: A mass with spiculated margins is almost
pathognomonic of malignancy. The abnormal axillary
lymph node is suggestive of metastatic disease. These
features make carcinoma the most likely diagnosis.
Although a few benign processes can present as spiculated
lesions, biopsy is indicated to exclude malignancy.
• Post-traumatic scarring and fat necrosis: There is
no history of prior trauma or breast surgery, making
this diagnosis unlikely. A postoperative scar can appear
as an area of architectural distortion or a spiculated
mass that should either decrease in size and density or
remain stable over time. Any increase in size should
prompt biopsy. To confirm the diagnosis of a surgical
scar, the site of the spiculated lesion must match the
location of the patient's cutaneous scar and the location
of the biopsied lesion on preoperative or needle
localization mammograms ( if available) .
• Radial scar/complex sclerosing lesion: Radial scars
are spiculated masses or regions of architectural distortion
that typically have long, thin spicules radiating
outward from a radiolucent center. However, occasionally
they can appear dense centrally and contain microcalcifications.
The large central mass in this case makes
the diagnosis of radial scar unlikely. The term radial
scar is used when the lesion measures < 1 cm and complex
sclerosing lesion is used when the lesion measures
> 1 cm. These benign proliferative lesions of unknown
etiology are usually nonpalpable and cannot be differentiated
reliably from carcinoma without biopsy.
• Abscess: Because there is no history of pain, swelling,
or erythema, this is an unlikely diagnosis. Abscesses
tend to occur in the subareolar region and often are
associated with mammographic changes of mastitis,
such as diffuse skin thickening and increased trabecular
density.
• Granular cell tumor: These benign tumors have a
spiculated appearance at mammography but are very
rare, making this diagnosis less likely. Biopsy is indicated
to differentiate these lesions from carcinoma.
• Extra-abdominal desmoid tumor: These are locally
invasive tumors that do not metastasize. Their mammographic
appearance mimics that of an invasive breast cancer,
requiring biopsy for diagnosis. These, too, are rare,
making the diagnosis unlikely in the case illustrated.
69
DIAGNOSIS: Infiltrating ductal carcinoma with
metastatic carcinoma to axillary lymph nodes.
KEY FACTS
CLINICAL
• Breast cancer is the most common malignancy in
American women, excluding skin cancers. After lung
cancer, it is the second leading cause of cancer death
among women.
• According to current estimates, breast cancer will be
diagnosed in approximately 1 in 8 women in their
lifetime.
• Invasive ductal carcinoma, not otherwise specified,
comprises 65% to 80% of invasive breast cancers. The
second most common type is invasive lobular carcinoma,
accounting for 3% to 1 4% of cases. Other, less
common specific forms of ductal carcinoma include
medullary, mucinous, papillary, and tubular carcinoma.
RADIOLOGIC
• A spiculated mass, characterized by lines radiating outward
from a central mass, is the most common mammographic
appearance for invasive ductal carcinoma.
• Spiculated margins usually signifY invasion.
• Spiculated projections result from ( 1 ) a desmoplastic
response (connective tissue proliferation ) that distorts
the adjacent tissue, ( 2 ) tumor infiltrating into the surrounding
tissue, or ( 3 ) both conditions.
• A spectrum of mammographic appearances can be seen
with invasive ductal carcinoma, including: ( 1 ) masses
with either spiculated, microlobulated, indistinct, and
circumscribed margins; ( 2 ) architectural distortion;
and ( 3 ) focal asymmetric or developing densities.
SUGGESTED READING
Adler D D . Mammographic Evaluation of Masses. In D B Kopans
(ed), SyUabus: A Categorical Course in Breast Imaging. Oak
Brook, IL: RSNA, 1 995; 1 07-1 16.
De Paredes ES. Atlas of Film-Screen Mammography. Baltimore:
Williams & Wilkins, 1992.
Feig SA. Breast masses: Mammographic and sonographic evaluation.
Radiol Clin North Am 1992;30:67-92.
Smitll RA. The Epidemiology of B reast Cancer. In DB Kopans (ed),
Syllabus: A Categorical Course in Breast Imaging. Oak Brook,
IL: RSNA, 1995;7-20.

Front 34

Screening mammogram in a 70-year-old woman, status post right lumpectomy and
radiation therapy for treatment of carcinoma.

Back 34

DIFFERENTIAL DIAGNOSIS
• Postoperative and postradiation changes of right
breast: This is the best diagnosis given the history.
• Edema: This diagnosis is less likely because edema is
commonly bilateral, with no associated mass or focal
distortion. Correlation with physical exam is helpful.
• Inflammatory carcinoma: Inflammatory carcinoma
has prominent, diffuse asymmetric density and skin
thickening. In its pure form, there is no focal mass or
distortion, but in many cases, there is a focal mass-like
density. Clinical presentation and physical exam are
important correlates, which demonstrate an erythematous,
nontender breast with peau d'orange appearance
of the skin. This diagnosis is considered less likely due
to the history of radiation therapy. Inflammatory carcinoma
also would not be expected to be associated with
dystrophic calcifications.
• Mastitis: Mastitis presents with a clinical history of
tenderness and fever, not present in this case. Physical
exam reveals cutaneous inflammatory changes and tenderness.
Focal mass is usually not present unless there
is an abscess. B iopsy is indicated if there is incomplete
resolution with antibiotic therapy.
+ DIAGNOSIS: Postoperative and postradiation
changes following lumpectomy and radiation therapy.
+ KEY FACTS
CLINICAL
• Lumpectomy creates focal distortion of normal breast
parenchyma at the site of the tumor. Radiation causes
fibrosis throughout the breast and can enhance the
distortion created by the surgical excision.
• Skin thickening and asymmetry in breast size may be
evident on clinical exam.
RADIOLOGIC
71
• Diagnosis of postoperative distortion can be confirmed
by correlating post-therapy films with preoperative
films showing the site of the tumor and needle localization
done before the surgical excision.
• Postoperative distortion and asymmetric increased density
due to surgery and radiation are most prominent
on the first post-therapy film done 6 to 1 2 months
after therapy.
• Distortion and asymmetric density gradually stabilize
or resolve over time, usually 2 . 5 to 3 . 0 years following
therapy.
• Dystrophic calcifications are a commonly associated
finding, particularly at the lumpectomy site .
Radiation and surgery can also cause benign fat
necrosis calcifications.
• Recurrent tumor can occur at the site of the primary
tumor. Increased mass, distortion, or malignantappearing
calcifications are signs that may indicate
recurrence. These findings should prompt biopsy.
+ SUGGESTED READING
Mendelson EB. Evaluation of the post-operative breast. Radiol Clin
North Am 1992;30 : 1 07- 1 38 .

Front 35

Diagnostic mammogram in a 33-year-old woman with pain in her left breast.
Sixteen years ago she underwent breast augmentation with silicone implants; the
right implant was ruptured and replaced 3 years before the mammogram.

Back 35

DIFFERENTIAL DIAGNOSIS
• Ruptured silicone implant with free silicone
extravasation into the left axilla: This is the best
diagnosis because the high-density nodules in the axilla
are equal in density to the silicone prosthesis, resulting
from migration of free silicone away from the ruptured
prosthesis. The lobulated contour of the prosthesis is
not specific for implant rupture if seen as an isolated
finding but should raise the question of rupture and
prompt further evaluation.
• Breast carcinoma metastatic to axillary lymph
nodes: This diagnosis is unlikely because the density of
the nodules in the axilla is equal to silicone, higher
even than expected for nodes involved with metastatic
disease . In addition, there are no breast lesions that are
suspicious for carcinoma.
• Sarcoidosis: Axillary lymph nodes can be seen at
mammography in patients with sarcoidosis. However,
the process is usually bilateral, and nodes are usually
enlarged. Abnormal lymph nodes associated with sarcoidosis
are denser than normal fatty-replaced lymph
nodes but do not have density as high as silicone, making
this an unlikely diagnosis in this case.
+ DIAGNOSIS: Ruptured silicone prosthesis on
the left, with residual free silicone seen 1 year later.
KEY FACTS
CLINICAL
• Rupture of prostheses (intracapsular or extracapsular)
is considered a major complication of prosthesis placement,
which necessitates surgical explantation of the
ruptured implant.
• Intracapsular rupture occurs when the gel escaping
from a ruptured implant is contained within the surrounding
fibrous capsule.
• Extracapsular rupture occurs when free silicone from a
ruptured implant extends outside of the fibrous capsule.
This free silicone is difficult to remove completely
at surgery and can stimulate a granulomatous reaction
within the breast.
73
• Silicone granulomas can cause a palpable mass which is
difficult to differentiate from carcinoma.
RADIOLOGIC
• When extracapsular free silicone is present, the diagnosis
of rupture can often be made mammographically
because the density of the free silicone within the
breast tissue is higher than that of other structures.
• The presence of extracapsular silicone is often diagnostic
of in1plant rupture. However, sometimes prior films
are needed to document the source of the rupture. For
instance, in a patient in whom a previously ruptured
implant has been replaced, prior films would be needed
to determine which implant was the source of the
extracapsular silicone.
• Ruptures that occur posteriorly or ruptures in which
only a small amount of sihcone escapes into the breast
parenchyma may not be detected mammographically
because they are either not included on the image or
the dense prosthesis obscures visualization of the free
silicone. In these situations, other imaging studies,
such as MRI or sonography, are necessary to make the
diagnosis.
• Mammography cannot detect intra capsular rupture
reliably. MRI has the highest sensitivity and specificity
for diagnosing intracapsular rupture.
+ SUGGESTED READING
Berg WA, Caskey Cl, Hamper UM, et al. Diagnosing breast implant
rupture with MR imaging, US, and mammography. Radiographies
1 993; 1 3 : 1 323-1336.
Berg WA, Caskey Cl, Hamper UM, et a1. Single- and double-lumen
silicone breast implant integrity: Prospective evaluation of MR
and US criteria. Radiology 1995;1 97:45-52.
Destouet JM, Monsees BS, Oser RF, et a1. Screening mammography
in 350 women with breast implants: Prevalence and findings of
implant complications. AJR Am J Roentgenol 1992 ; 1 5 9 :
973-987.
Everson Ll, Parantainen H , Dedie T, et a1. Diagnosis of breast
implant rupture: Imaging findings and relative efficacies of imaging
techniques. AJR Am J Roentgenol 1 994; 1 63:57-60.
Gorczyca DP, Sinha S, Ahn CY, et a1. Silicone breast implants in
vivo: MR imaging. Radiology 1992 ; 1 8 5 :407-4 1 0 .

Front 36

Diagnostic mammogram in a 52-year-old female, status post left mastectomy for
breast cancer and right subcutaneous mastectomy with reconstruction.

Back 36

DIFFERENTIAL DIAGNOSIS
• Fat necrosis: Low-density ( fatty) masses in the breast
are almost always benign. A low-density mass associated
with dystrophic ( bizarre, irregular, and plaque-like)
calcifications, as is seen in this case, is most consistent
with fat necrosis. Dystrophic calcifications can be seen
with fat necrosis secondary to trauma, surgery, or radiation
therapy.
• Carcinoma: Malignant calcifications are usually <0.5
mm in size, ranging from minute up to 3 mm. Many
of the calcifications in the case illustrated are >2 to 3
mm in size and have benign rim and plaque-like
shapes, making carcinoma an unlikely diagnosis.
• Fibroadenoma: Although fibroadenomas can contain
large, bizarre, irregular calcifications, as seen in this
case, involuting fibroadenomas typically contain coarse
or "popcorn-like" calcifications. The mass in this case
is not consistent with a fibroadenoma because it has
low density, as opposed to fibroadenomas, which are
water-density masses.
• Secondary hyperparathyroidism with metastatic
calcifications: Patients with hypercalcemia can develop
coarse amorphous calcifications within the breast.
However, calcifications would not be expected to be
rim-like or associated with a radiolucent mass, making
this diagnosis unlikely.
+ DIAGNOSIS: Fat necrosis secondary to prior
surgery.
+ KEY FACTS
CLINICAL
• Fat necrosis is an inflammatory response that is usually
due to trauma or surgery but can be idiopathic.
75
• Fat necrosis can be difficult to distinguish from carcinoma
on both physical examination and mammography.
• Clinically, fat necrosis can present as a hard painless
mass that is ill-defined and poorly mobile. Skin thickening
or retraction may also be identified, increasing
the clinical suspicion of carcinoma.
• In some cases, the traumatic event leading to fat
necrosis is forgotten or unknown.
RADIOLOGIC
• At mammography, fat necrosis has a wide spectrum of
appearances, ranging from well-defined oil cysts to
spiculated masses that simulate carcinoma.
• Calcifications are commonly associated with fat necrosis.
When calcifications first appear they can be small and
pleomorphic, mimicking malignant calcifications.
However, they usually evolve into larger, coarse, plaquelike
calcifications that have a more benign appearance.
• Early dystrophic calcifications can be difficult to distinguish
from malignancy. Magnification mammography
and close (4 to 6 months) mammographic follow-up
are often indicated in patients with suspected fat
necrosis. Occasionally biopsy is necessary to exclude
malignancy.
+ SUGGESTED READING
De Paredes ES. Atlas of Film-Screen Mammography. Baltimore:
Williams & Wilkins, 1992.
Feig SA. Mammographic Evaluation of Calcifications. In DB
Kopans, EB Mendelson (eds), Syllabus: A Categorical Course in
Breast Imaging. Oak Brook, IL: RSNA, 1995.
Mendelson EB. Evaluation of the post operative breast. Radiol Clin
North Am 1992;30 : 1 07-1 3 8 .
Morrow M . Breast Trauma, Hematoma, and Fat Necrosis. In JR
Harris, S Hellman, IC Henderson, DW Kinne (cds), Breast
Disease. Philadelphia: Lippincott, 1 99 1 .

Front 37

Screening mammogram in a 36-year-old woman. The family history is significant
for a sister with premenopausal breast carcinoma.
B

Back 37

DIFFERENTIAL DIAGNOSIS
• Fibroadenoma: The mammographic and sonographic
features of this lesion, as well as the young age of the
patient, are typical of a fibroadenoma.
• Carcinoma: Some well-defined carcinomas ( medullary,
mucinous, papillary) can have these mammographic
and sonographic features. However, these tumors are
uncommon tumors, making this diagnosis less likely.
• Phyllodes tumor: At mammography, phyLlodes tumors
are well-circumscribed, often large masses indistinguishable
from fibroadenomas or other tumors. The sonographic
appearance of a phyLlodes tumor can be identical
to the lesion in the case illustrated. However, many
phyLlodes tumors contain cystic spaces, producing a
more heterogeneous sonographic appearance.
• Cyst: The mammographic features of a cyst can be
identical to the appearance of the mass in this case.
However, the sonogram reveals a solid mass, not a
simple cyst.
DIAGNOSIS: Fibroadenoma.
+ KEY FACTS
CLINICAL
• Fibroadenomas are common benign breast lesions that
occur in premenopausal and perimenopausal age
groups.
• On physical examination, the mass is usually firm, welldefined,
and mobile.
• Growth of fibroadenomas is stimulated by hormonal
influence.
77
• Fibroadenomas can be multiple and bilateral. Multiplicity
and bilaterality are more common in black women.
RADIOLOGIC
• The management of a probably benign mass involves
close mammographic follow-up at 6-month intervals.
Mammographic follow-up is less expensive and less
invasive than surgical biopsy. Only a small proportion
( - 1 . 5% ) of well-circumscribed masses are found to be
malignant tumors.
• In the small proportion of masses that prove to be
malignant tumors, the delay in diagnosis due to mammographic
follow-up does not alter the prognosis
when compared to diagnosing the cancer at the time
of initial screening.
• In the case illustrated, the mass was considered probably
benign by mammographic and sonographic features.
However, biopsy was performed because the
mass was new and the patient had a strong family history
for premenopausal breast carcinoma.
• Stereotactic biopsy is often useful in these cases to
make the diagnosis because it is less invasive and less
expensive than open surgical biopsy.
+ SUGGESTED READING
Liberman L, Bonaccio E, Hamele-Bena D, et aI. Ben.ign and malignant
phyllodes tumors: Mammographic and sonographic findings.
Radiology 1996;198 : 1 22-1 24.
Sickles EA. Nonpalpable, circumscribed, noncalcified solid breast
masses: Likelihood of malignancy based on lesion size and age of
patient. Radiology 1994;192 :439-442 .
Smith BL. Fibroadenomas. In JR Harris, S Hellman, Ie Henderson,
DW Kinne (eds), Breast Diseases. Philadelphia: Lippincott,
1991 ;34-37.

Front 38

Screening mammogram in a 64-year-old women. A true lateral mammogram was performed
because of a questionable area of distortion anteriorly on the right that did
not persist. A sonogram of the superior right breast was subsequently performed.

Back 38

DIFFERENTIAL DIAGNOSIS
• Breast carcinoma: This diagnosis should be considered
until proved otherwise. After the lesion is seen
initially on the true lateral image, every effort should
be made to confirm the location of the lesion, including
exaggerated craniocaudal views, sonography, or
even stereotactic localization if necessary.
• Summation artifact: Summation artifact can sometimes
produce an apparent focal density on one view.
However, this diagnosis was proved incorrect when
sonography showed a solid mass was present.
+ DIAGNOSIS: Infiltrating ductal carcinoma.
+ KEY FACTS
CLINICAL
• Carcinomas can occur in areas of the breast that are
not routinely imaged at screening or are difficult to
localize on diagnostic exams. This is one reason for the
7% to 1 0% false-negative rate of screening mammography
in detecting carcinoma. Therefore, a patient
should not be considered completely screened until
evaluated with both physical exam and mammography.
RADIOLOGIC: EVALUATING A LESION
SEEN IN ONE VIEW
• Attempts must be made to ensure that the region of
abnormality is included on the orthogonal view (as in
this case, repeated exaggerated craniocaudal views
attempted to localize the lesion ) .
• I f the abnormality i s not seen i n the two views, summation
artifact is a consideration . However, other
modalities may be necessary to confirm this diagnosis.
79
• If a lesion is seen on the screening mediolateral
oblique mammogram only, a true lateral will be useful
in determining how the lesion moves in relation to the
central axis of the breast. Lateral lesions move lower in
the breast on the true lateral view, while medial lesions
move up in the breast.
• If a lesion is seen on the screening craniocaudal mammogram
only, a roll craniocaudal view or a craniocaudal
mammogram at 5-degrees tube angulation can be
performed. If the superior part of the breast is rolled
laterally and the lesion moves laterally, then it can be
determined to be in the superior portion of the breast.
Likewise, if the lesion moves medially when the superior
breast is rolled laterally, the lesion can be shown to
be inferior in the breast.
• Sonography and physical examination are often useful in
localizing lesions seen in only one view, as in this case.
• If necessary, the finding can be confirmed to be a true
mass using stereotactic localization. CT or MRI can
also be used to localize a lesion seen in one view.
+ SUGGESTED READING
Kopans DB, Waitzkin ED, Linetsky L, et al. Localization of breast
lesions identified on only one mammographic view. AJR Am J
Roentgenol 1987; 1 49 : 39-4 l .
Sickles EA. Practical solutions to common mammographic problems:
Tailoring the examination . AJR Am J Roentgenol 1988 ; 1 5 1 :
3 1 -39.
SWaim CA, KOpallS DB, McCarthy KA, et al. Localization of occult
breast lesions: Practical solutions to problems of trimgulation.
Racliology 1987; 1 63:577-578.

Front 39

Screening mammogram in a 49-year-old premenopausal woman. She had no
palpable abnormality or history of surgery.

Back 39

DIFFERENTIAL DIAGNOSIS
• Asynunetric breast tissue: This is the best diagnosis
because the density has the appearance of normal
parenchyma with no underlying suspicious characteristics.
No corresponding palpable mass was identified to
raise the suspicion for other processes.
• Postoperative change with removal of breast tissue
from the contralateral breast: This diagnosis is
unlikely because there is no history of prior breast
surgery.
• Carcinoma: Although carcinoma may present as an
asymmetric density, there is no associated palpable
mass or associated suspicious mammographic feature
to suggest malignancy.
+ DIAGNOSIS: Asynunetric breast tissue.
+ KEY FACTS
CLINICAL
• Asymmetric breast tissue density has been described as
a secondary sign of malignancy, but this is unlikely
unless there is a corresponding palpable abnormality.
• The area of asymmetry should be evaluated with a
careful physical breast examination. If there is a palpable
abnormality or palpable asymmetry, biopsy should
be recommended.
81
• A clinical history of prior breast surgery is important.
For instance, asymmetry can be due to removal of tissue
during biopsy of the contralateral breast.
RADIOLOGIC
• At least 3% of women have asymmetric breast tissue
that appears as increased volume or density relative to
the contralateral breast. This is most commonly seen
in the upper outer quadrants. It reflects normal asymmetric
development or variable response to hormonal
stimulation.
• Additional mammographic views, including focal compression
and magnification, may be necessary to evaluate
the asymmetric density for mass, architectural distortion,
or microcalcifications.
• Asymmetric density represents a normal variant if the
glandular structures and fat are normally dispersed in
the area with no mass, distortion, or microcalcifications,
and no corresponding palpable abnormality.
• Comparison with prior films or close interval mammographic
follow-up can be recommended to document
the stability of the pattern.
+ SUGGESTED READING
Kopans DB (ed ) . Breast Imaging. Philadelphia: Lippincott, 1989.
Kopans DB, Swann CA, White CA, et al. Asymmetric breast tissue.
Radiology 1 989; 1 7 1 :639-643 .

Front 40

A 43-year-old asymptomatic woman presenting for a screening mammogram.

Back 40

Hamartoma (fibroadenolipoma): The encapsulated,
well-circumscribed mass with internal fat and fibroglandular
tissue in disorganized array is typical of a hamartoma.
These findings make this the best diagnosis.
• Intramammary lymph node: Normal intramammary
lymph nodes are typically round, oval, or lobulated
isodense masses that measure < 1 cm in size and usually
contain a central fatty hilum. The size of the
lesion presented here and the haphazardly arranged
fatty and soft-tissue components make lymph node an
unlikely diagnosis.
• Galactocele: Galactoceles are milk-containing cysts that
appear as a radiolucent or mixed-density circumscribed
mass that can have a mottled appearance, mimicking a
hamartoma. A fat-fluid level can be seen on horizontal
beam radiograph, which is not present in this case. This
diagnosis is also unlikely in the present case because
there is no history of current or recent lactation.
• Lipoma: Lipomas are circumscribed, fat-containing
masses that are radiolucent on mammograms.
However, in addition to radiolucent regions, the lesion
presented here has regions that are isodense with
breast parenchyma. This finding would not be found
in a pure lipoma and makes this diagnosis unlikely.
• Oil cyst: Oil cysts would also be a consideration in a
lesion that was predominantly radiolucent. Again, the
mixed density arranged in a haphazard pattern argues
against this diagnosis in the case illustrated.
DIAGNOSIS: Hamartoma.
+ KEY FACTS
CLINICAL
• Hamartomas are uncommon, benign breast tumors containing
ducts, lobules, adipose tissue, and fibrous tissue in
varying proportions. Smootll muscle can also be present.
83
• Hamartomas can be discovered incidentally on screening
mammography or present clinically as a painless
breast lump or enlarging breast.
• When palpable, hamartomas are usually firm, smooth,
and mobile.
• Hamartomas usually grow slowly but can reach a large
size, producing marked asymmetry of the breast.
RADIOLOGIC
• The characteristic mammographic appearance of a
hamartoma is a circumscribed oval or round mass
composed of mixed radiolucent and radiodense areas.
This classic appearance is pathognomonic for a hamartoma,
obviating the need for surgical excision.
• Not all hamartomas have a classic mammographic
appearance . The mass can vary from relatively radiolucent
to very dense, depending on the proportions of
fibrous and fatty tissue. Sometimes tlle mass can be
uniformly dense with obscured margins. In these cases,
me appearance is nonspecific, and biopsy may be
required for diagnosis.
• The mass displaces adjacent fibroglandular tissue, often
leaving a thin intervening radiolucent zone. It usually
has a well-defined margin and can appear encapsulated.
• If small or in a dense breast, hamartomas can be inapparent
at mammography.

Front 41

Screening mammogram in a 36-year-old asymptomatic woman with no past surgical
history. She has no palpable breast masses.

Back 41

Inflltrating ductal carcinoma: The mammographic
finding of a large area of architecntral distortion associated
with pleomorphic microcalcifications is consistent
with infiltrating carcinoma and is an indication for
biopsy. However, the absence of a palpable mass in this
large area of distortion raised the possibility of another
diagnosis.
• Complex sclerosing lesion/radial scar: Because this
lesion is not palpable, a complex sclerosing lesion is a
diagnostic consideration . A complex sclerosing lesion
often appears at mammography as an area of architectural
distortion or a spiculated mass with a lucent center.
However, any area of distortion that does not correspond
to a surgical scar must be biopsied to exclude
malignancy.
• Postsurgical scar: Surgical scars often appear as an
area of architectural distortion that may appear somewhat
mass-like in one view but elongated in another
view. Although the mammographic appearance of a
surgical scar can be similar to the findings in this case,
this diagnosis is not possible because there is no history
of surgical biopsy.
DIAGNOSIS: Complex sclerosing lesion.
+ KEY FACTS
CLINICAL
• The term complex sclerosing lesion refers to a lesion that
measures > 1 0 mm. Similar lesions measuring < 1 0 mm
are termed radial scar, infiltrating epitheliosis, elastosis,
or indurative mastopathy.
• Complex sclerosing lesions are not usually palpable.
They are most often detected at mammography.
• Histologically, complex sclerosing lesions are characterized
by a central area of elastosis surrounded by a disorganized
array of tubules. They can also contain
papillomas, apocrine change, and sclerosing adenosis.
85
• Radial scars and complex sclerosing lesions were previously
thought to have an association with ntbular carcinoma.
This has been refuted because those cases in
question have proved to represent ntbular carcinomas
misdiagnosed histologically, not radial scars.
• Excisional biopsy is necessary to differentiate complex
sclerosing lesions from malignant lesions. They can be
difficult to differentiate histologically from ntbular carcinoma
on core biopsies. Therefore, excisional biopsy
is preferred over stereotactic biopsy when this diagnosis
is considered.
RADIOLOGIC
• Complex sclerosing lesions often present as focal areas
of architectural distortion or a spiculated mass with
central density.
• Associated rnicrocalcifications have been reported in
14% to 40% of cases.
• Central lucency can be evident, but this does not differentiate
this lesion from malignant lesions reliably.
• The length of spiculations cannot differentiate these
lesions from malignant lesions reliably.

Front 42

A 45-year-old woman presenting for screening mammography 2 years after lumpectomy
and radiation therapy to the upper inner quadrant of the right breast for carcinoma.

Back 42

Sclerosing adenosis: Sclerosing adenosis is a benign
lobular proliferation that results in enlargement and
distortion of the lobules. Sclerosing adenosis can have
many mammographic appearances. However, the associated
calcifications are usually seen diffusely throughout
the breast, characterized by uniformly dense and
round or amorphous intralobular calcifications, unlike
the calcifications in this case. Sclerosing adenosis sometimes
forms an isolated cluster of calcifications that
may require biopsy to differentiate them from malignant
lesions.
• Comedo carcinoma: This is the best diagnosis because
the calcifications in this case vary in size and density
and have irregular, linear, and branching shapes, all of
which are typical of comedo carcinoma in situ.
• Plasma cell mastitis: In plasma cell mastitis, calcific
deposits occur in areas of extruded cellular debris surrounding
inflamed ducts. Unlike the pleomorphic calcifications
in this case, secretory calcifications associated
with plasma cell mastitis are usually large ( > 0 . 5
m m ) and rod shaped, with uniform density, making
this diagnosis unlikely.
• Dystrophic calcifications from fat necrosis following
surgery and radiation therapy: Calcifications
associated with fat necrosis can sometimes mimic
malignant calcifications. When they first appear, they
can vary in size and density and have irregular, pleomorphic
shapes. These calcifications are often clustered,
being localized to the site of traumatic insult.
Dystrophic calcifications usually evolve over time to
coarser, plaque-like forms that have a more benign
appearance. In the case illustrated, the cluster of calcifications
is in the outer quadrant, lateral to the lumpectomy
site, making fat necrosis an unlikely diagnosis.
+ DIAGNOSIS: Comedo carcinoma in situ.
+ KEY FACTS
CLINICAL
• Comedo carcinoma is one of several forms of ductal
carcinoma in situ characterized histologically by central
87
necrosis within the involved ducts. Calcification of the
necrotic tissue is common. Tumor cells often demonstrate
nuclear pleomorphism, and mitotic cells are frequently
seen.
• Comedo carcinoma in situ can be present alone or
associated with invasive ductal carcinoma.
• Comedo carcinoma has a higher recurrence rate than
low-grade forms of carcinoma in situ.
RADIOLOGIC
• A cluster of microcalcifications is considered suspicious
if it contains five or more indeterminate calcifications
localized to a 1 -cm3 area. However, the specificity of
this finding is low, as carcinoma may be identified in
only 1 0% to 3 5 % of cases with this mammographic
appearance.
• Comedo carcinoma most commonly presents mammographically
as clustered microcalcifications.
• Calcifications associated with comedo carcinoma vary
in size, shape, and density. Fine linear or branching
calcifications due to necrotic debris within the central
portion of the ducts are seen frequently and may be
associated with rounded or granular calcifications.
• The finding of new microcalcifications at the lumpectomy
site is the most common mammographic feature
of early recurrence. For this reason, magnification
images of lumpectomy sites are performed routinely in
the follow-up of patients who have undergone lumpectomy
and radiation therapy for carcinoma.

Front 43

Diagnostic mammogram in a 58-year-old woman with a palpable lump in the right
central breast and a clinical history of melanoma. There were no prior mammograms
for comparison.

Back 43

Cysts: Cysts are commonly detected, well-circumscribed
breast masses that are often multiple and bilateral
and can fluctuate in size or resolve over time. This
diagnosis would be a good consideration in this case.
However, cysts cannot be confirmed by mammography
alone. Sonography or needle aspiration would be necessary
to complete the evaluation. These lesions
proved solid at sonography, making this an incorrect
diagnosis.
• Fibroadenomas: Fibroadenomas are also common
breast masses that cannot be differentiated from cysts or
other solid circumscribed masses by mammography
unless they contain characteristic coarse, "popcorn-like"
calcifications. Fibroadenomas are often oval or lobulated
in shape and tend to be oriented toward the nipple.
This diagnosis should be considered in this case but cannot
be confirmed by this mammographic appearance .
• Metastases: Metastases t o the breast are usually wellcircumscribed
round masses that cannot be differentiated
from cysts or fibroadenomas by mammography
alone. Knowledge of a history of an extramammary
malignancy is necessary for the diagnosis of metastases
to be considered, and biopsy is necessary to confirm
the diagnosis.
• Lymph nodes: The masses in this case are not consistent
with benign intramarnmary lymph nodes because benign
lymph nodes are typically oval or reniform in shape and
have a hilar notch or lucent center. Intramarnmary nodes
tend to be <l cm in size. Enlarged reactive or metastatic
nodes could have this appearance .
• Multifocal or multicentric breast cancer: Multifocal
breast cancer usually presents at mammography as
multiple, ill-defined or spiculated masses or multiple
clusters of microcalcifications, making this diagnosis
unlikely in this case. However, primary breast cancers
rarely present as multiple, unilateral, well-circumscribed
masses ( for example, an invasive papillary carcinoma
with satellite nodules) .
+ DIAGNOSIS: Metastatic melanoma o f the right
breast.
+ KEY FACTS
CLINICAL
• Melanoma is the eighth most prevalent malignancy in
the United States, with approximately 32,000 new
cases in the United States each year.
89
• The most common sites for metastases from melanoma
are skin, subcutaneous tissue, lymph nodes, lungs,
bone, central nervous system, and liver.
• Although the breast is an unusual site for melanoma
metastases, melanoma is the most common source of
metastases to the breast. Lymphoma and lung carcinoma
are also common causes of metastases to the breast.
• When metastases to the breast are considered in a
patient with appropriate history and physical examination,
mammograms are necessary to exclude primary
breast carcinoma, support the clinical suspicion of
metastases, and monitor any therapeutic response following
treatment.

Front 44

A 73-year-old asymptomatic woman presenting for a screening mammogram who
had begun hormone replacement therapy 1 year previously. She had no family history
of breast cancer.

Back 44

Glandular stimulation from hormone replacement
therapy: Tlus is the best diagnosis because the change
has occurred diffusely and bilaterally, without other
associated suspicious features. The clinical history is
also consistent with this diagnosis.
• Edema: This diagnosis is less likely because the change
predominantly involves the breast parenchyma, witl1-
out skin or trabecular thickening, which is commonly
associated with edema.
• Mastitis: This diagnosis is unlikely because tl1e change
is bilateral. Mastitis can present as a segmental area of
increased density and can be associated with abscess.
The clinical history is also inconsistent with mastitis, as
the patient was asymptomatic.
• Carcinoma: Although locally advanced breast carcinoma
can present as a diffuse increase in density, the
bilateral change makes this unlikely. Other features
such as skin and trabecular thickening often seen with
inflammatory carcinoma are not present, and the
breasts do not appear smaller and contracted compared
with the prior study.
DIAGNOSIS: Glandular stimulation from hormone
replacement therapy.
KEY FACTS
CLINICAL
• Hormone replacement therapy is relatively common
among postmenopausal women due to the beneficial
result of decreasing cardiovascular disease and osteoporosis.
• Estrogen promotes growth of ducts and stimulates surrounding
connective tissue. Progesterone promotes
growth of lobuloalveolar structures and differentiation
of ductal cells.
• Treatment with estrogen promotes enlargement of
cysts and fibroadenomas. Treatment with a combination
of estrogen and progesterone is associated with
diffuse increase in fibroglandular tissue.
91
• A number of smdies have evaluated the risk of breast
cancer for women on hormone replacement therapy.
The results are conflicting, but tl1ere appears to be a
slight increase in risk based on the duration of use.
RADIOLOGIC
• Effects of hormone replacement therapy that can be
apparent on mammograms include symmetric or asymmetric
increase in breast density, increase in size of
fibroadenomas, and development or increase in size of
cysts.
• Mammographic changes develop in 24% of postmenopausal
women undergoing hormone replacement
therapy.
• Man1ffiographic changes are more common in women
treated with the combination of estrogen and progesterone
than in women treated with estrogen alone.
• Asymmetric or focal increase in breast density is more
problematic. It may be interpreted as a developing
density. Further evaluation may include breast ultrasound,
physical correlation, mammographic follow-up
with or without cessation of hormones, or even biopsy
to exclude malignancy.

Front 45

Screening mammogram in a 42-year-old woman

Back 45

Benign calcifications: This is the best diagnosis due
to microcalcification number and morphology. Stability
should be established by follow-up mammography.
• Cutaneous calcifications: Cutaneous calcifications are
usually located along the periphery of the breast and
are round with lucent centers, unlike the calcifications
in this case.
• Calcifications highly suspicious for malignancy: This
diagnosis is less likely because the calcifications in this
case are few in number and morphology of the cluster
is uniform, not linear, branching, or pleomorphic.
+ DIAGNOSIS: Probably benign calcifications.
+ KEY FACTS
CLINICAL
• The calcifications described in this case form from
benign processes such as focal sclerosing adenosis,
focal fibrosis, and occasionally, early manifestations of
fat necrosis.
RADIOLOGIC
• Isolated clusters of calcifications can display features
that indicate a low probability of malignancy. They are
as follows:
93
1 . Such calcifications are round or punctate and are
uniform in shape and density, allowing for variation
in size.
2. The number of calcifications within the isolated
cluster is five or less.
3. Calcifications are not associated with any other
mammographic abnormality such as a mass, distortion,
or focal asymmetry.
• Spot compression magnified images are necessary for
initial evaluation of number and morphology. Spot
compression magnified images are also used in followup
examinations.
• Such indeterminate calcifications are usually managed
with close interval mammographic follow-up.
Calcifications are reimaged at 6, 1 2 , and 24 months.
Any change in the number or morphology should be
viewed as suspicious for possible malignancy, and biopsy
may be indicated. Stability over a 24-month period
is generally considered as an indication of a benign
process. After this period of close follow-up, a routine
screening schedule is resumed.
+ SUGGESTED READING
Feig SA. Mammographic evaluation of calcifications. RSNA
Categorical Course in Breast Imaging 1 995;93-105.
Sickles EA. Breast calcifications: Mammographic evaluation.
Radiology 1986;1 60:289-293.

Front 46

Diagnostic mammogram in a 72-year-old woman who presented with a 2-cm palpable
mass in the upper inner quadrant of the right breast. The family history was
significant for a sister with postmenopausal breast carcinoma.

Back 46

REASONS FOR A FALSE-NEGATIVE
MAMMOGRAM
• Poor-quality study: In this case, positioning and technical
factors are optimal, making this an unlikely reason
for a false-negative mammogram. The radiologist is
responsible for assuring high-quality mammography.
• The lesion is not imaged: Breast tissue can occur in
areas not covered on a routine mammogram . In this
case, the lesion was close to the areola and should have
been included on both images. A cutaneous marker
should be placed at the site of the mass and images
repeated to confirm mass location has been included
on the films.
• Error of interpretation: In reviewing this case, no
mammographic abnormality was identified, even in
retrospect.
• Mass obscured by dense breast tissue: In breasts
with very dense breast tissue, even a well-defined
mass can be completely obscured by breast tissue,
making this the most common cause of a false- negative
mammogram.
• Infiltrating lobular carcinoma: Unlike infiltrating
ductal carcinoma, infiltrating lobular carcinoma does
not form a discrete mass. The malignant cells invade
the surrounding breast tissue in a single-file fashion
and often cannot be distinguished from surrounding
breast parenchyma at mammography.
• DIAGNOSIS: Infiltrating lobular carcinoma.
KEY FACTS
CLINICAL
• Infiltrating lobular carcinoma feels like an area of
thickening rather than a discrete lump on physical
examination .
95
• At the cellular level, it invades the surrounding breast
tissue in a linear, single-file fashion.
• Metastases to axillary lymph nodes are common at the
time of diagnosis.
RADIOLOGIC
• Infiltrating lobular carcinoma can appear as a slowly
developing asymmetric density or an area of mild
architectural distortion, but it often is not seen on
mammograms.
• Infiltrating lobular carcinoma has a variety of sonographic
appearances, but no findings or only a nonspecific
region of posterior acoustic shadowing may be
present.
SUGGESTED READING
Krecke KN, Gisvold JJ. Invasive lobular carcinoma of the breast:
Mammographic findings and extent of disease at diagnosis in 1 84
patients. AJR Am J Roentgenol 1993; 1 6 1 :957-960.
Paramagul CP, Helvie MA, Adler DD. I nvasive lobular carcinoma:
Sonographic appearance and role of sonography in improving
diagnostic sensitivity. Radiology 1995 ; 1 9 5 : 2 3 1 -234.
Rosen, PP. The Pathology of Invasive Breast Carcinoma. In JR
Harris, S HeUman, IC Henderson, DW Kinne (cds), Breast
Diseases. Philadelphia: Lippincott, 1 99 1 ;272-276.

Front 47

Screening mammogram in a 73-year-old female. Family history is significant for a
sister with postmenopausal breast carcinoma. There is no past surgical history or
history of hormone replacement therapy.

Back 47

Breast carcinoma with metastatic disease to an
intramammary lymph node: A developing asymmetric
density within the breast must be viewed with suspicion
because this is one mammographic presentation
of breast carcinoma. The associated enlargement and
increased density of the intramammary lymph node
increases the suspicion for carcinoma with metastatic
disease, making this the best diagnosis .
• Mastitis with reactive lymph node: Mastitis can be
seen at mammography as a localized asymmetric density,
and intramammary lymph nodes can enlarge as a
result of infections of the breast . However, the patient
in this case was asymptomatic and had no physical
signs of infection, making this diagnosis unlikely.
• Focal glandular stimulation from hormone replacement
therapy: This process could cause a developing
density within the breast, with enlargement of nodules
corresponding to cyst formation. However, the patient
in the case illustrated has no history of hormone
replacement therapy, and the nodule seen in this case
was previously shown to represent an intramammary
lymph node.
• Normal asymmetric breast parenchyma: The mammographic
appearance of the asymmetric density in
this case could be consistent with asymmetric glandular
tissue . However, glandular tissue would not be expected
to increase over time without hormonal stimulation,
and the enlargement of the intramammary lymph
node could not be explained with this diagnosis.
+ DIAGNOSIS: Inflltrating ductal carcinoma with
1 /34 positive lymph nodes.
+ KEY FACTS
CLINICAL
• Infiltrating ductal carcinoma can be metastatic to intramammary
lymph nodes.
97
• Intramammary lymph nodes with metastatic involvement
are often palpable, located in the upper outer
quadrant of the breast . Careful physical examination in
this breast proved this node to be palpable.
RADIOLOGIC
• Infiltrating ductal carcinoma can present infrequently
as a developing asymmetric density. Any change in the
mammogram from one year to the next must be
explained.
• When an asymmetric density is identified on the mammogram,
additional focal compression images and
physical examination to evaluate for a palpable mass
are essential to complete the evaluation.
• When intramammary lymph nodes enlarge over time,
the breast must be inspected carefully for evidence of
primary breast carcinoma. Considerations in the differential
diagnosis of enlarged intramammary nodes
include metastatic disease from breast primary,
metastatic disease from extramammary malignancies,
and reactive change from inflammatory processes.

Front 48

Diagnostic mammogram in a 70-year-old woman who presented with a painless,
swollen erythematous right breast. There was no significant past medical history.

Back 48

Inflammatory carcinoma: The clinical presentation of
a painless, swollen, erythematous breast and the mammographic
findings of thickening of the skin and trabeculae
in association with a mass make this the most
likely diagnosis.
• Axillary mass obstructing the lymphatics: The
mammographic findings of the large axillary mass and
trabecular and skin thickening make this a reasonable
choice. However, this diagnosis would be ruled out
based on the physical examination because obstructed
lymphatics would not result in an inflamed, erythematous
appearance of the breast.
• Radiation therapy: Radiation therapy often results in
skin and trabecular thickening. However, there was no
history of radiation therapy in this case.
• Mastitis: Mammographic changes of skin and trabecular
thickening are often seen in cases of mastitis or cellulitis,
and the large arillary mass could represent reactive
lymph node(s) due to infection. In cases of mastitis,
however, skin and trabecular thickening are usually
localized to one segment or region, not spread diffusely
throughout the breast. Furthermore, the clinical history
of "painless" swelling of the breast is not consistent
with mastitis.
• Congestive heart failure: Congestive heart failure can
result in unilateral skin and trabecular thickening in
the dependent breast if the patient lies on one side.
However, the mass in the right axilla makes this diagnosis
unlikely.
DIAGNOSIS: Inflammatory breast carcinoma.
+ KEY FACTS
CLINICAL
99
• Inflammatory breast carcinoma is a diffuse carcinoma
involving all portions of the breast, including the dermal
lymphatics.
• On physical examination, the patient has a painless,
red, hot, swollen breast with a peau d'orange appearance
of the skin.
• Antibiotics ( used if mastitis is considered in the differential
diagnosis ) can result in clinical regression of
symptoms of inflammatory carcinoma. Biopsy is often
necessary to make the diagnosis.
• The diagnosis can be made by a punch biopsy of the
skin to determine the presence of carcinoma in the
dermal lymphatics.
RADIOLOGIC
• The involved breast is asymmetrically dense compared
to the contralateral breast.
• Thickening of the skin and trabeculae are typically
present throughout the involved breast.
• An underlying dominant mass may or may not be
present.

Front 49

Diagnostic mammogram in a 60-year-old woman who is status post lumpectomy
for infiltrating ductal carcinoma in the inferior portion of the right breast.

Back 49

Spiculated carcinoma: Carcinoma often presents as a
mass with spiculated margins or an area of architectural
distortion. The lesion in the case illustrated has no
central mass and corresponds to the site of prior biopsy,
making carcinoma a less likely diagnosis.
• Postsurgical or post-traumatic scar: A postsurgical
scar often appears as an area of architectural distortion
or a spiculated mass that decreases in size over time.
The site of the spiculated lesion must match the location
of the patient's cutaneous scar and the location of
the biopsied lesion on preoperative or needle localization
mammograms (if available). The lesion in the case
illustrated corresponds to the site of prior biopsy, making
this a likely diagnosis.
• Radial scar: Radial scars typically appear as lesions with
long, thin spicules radiating outward from a radiolucent
center. The lesion in the case illustrated has some of the
mammographic features of a radial scar. However, a
radial scar would not be expected to occur at a site of
prior biopsy, making this diagnosis less likely.
• Granular cell tumor: These benign tumors have a
spiculated appearance at mammography but are very
rare and would not be expected to occur at biopsy
sites, making this diagnosis unlikely.
• Extra-abdominal desmoid tumor: These are locally
invasive tumors that do not metastasize. Their mammographic
appearance mimics that of an invasive
breast cancer, requiring biopsy for diagnosis. These
lesions are rare, and location at a site of prior biopsy
would be unlikely.
+ DIAGNOSIS: Postsurgical scar.
+ KEY FACTS
CLINICAL
• Fibrosis and fat necrosis at a surgical site (or site of
trauma) can cause a spiculated mass or architectural
distortion simulating the appearance of tumor.
101
• On palpation, scars feel like an area of thickening,
whereas carcinomas feel more discrete and larger than
an associated abnormality seen on mammogram.
• History of surgery at the site of the mammographic
abnormality is helpful. The cutaneous surgical scar may
not always correlate with the parenchymal scar since
the surgeon may make the skin incision at some distance
from the lesion to be removed.
RADIOLOGIC
• Postsurgical or post-traumatic scars frequently present
as a spiculated mass or area of architectural distortion
on mammogram, which is often identical to the
appearance of carcinoma.
• Scars do not have a central mass or density after initial
postoperative seroma has resolved; central lucency is
commonly seen within the scar.
• The preoperative and needle localization mammograms
and specimen radiograph can be used to confirm that
the suspected scar correlates with the surgical site.
• If prior mammograms are not available but the density
is strongly suspected to be a scar, it can be further evaluated
with close-interval mammographic follow-up.
• A scar should decrease in density and distortion or
remain stable during follow-up.
• Any increase in size or density of a suspected scar warrants
biopsy.

Front 50

Diagnostic mammogram in a 62-year-old woman with pain in her left breast. She
had a right-sided modified radical mastectomy for carcinoma and a left-sided subcutaneous
mastectomy, with breast reconstruction bilaterally using silicone prostheses.
Subsequent sonogram and MRI of the left breast were performed.

Back 50

Intracapsular implant rupture: This is the best diagnosis
because MRl demonstrates numerous curvilinear
hypointense lines within the hyperintense silicone gel,
corresponding to the ruptured and collapsed shell of
the prosthesis ("linguine" sign ) . No silicone is seen
outside of the fibrous capsule.
• Extracapsular implant rupture: The mild contour
abnormality of the implant on the mammogram is a
nonspecific finding, but in conjunction with the clinical
symptoms, raised the question of implant rupture,
prompting further investigation using MRl . Neither
the mammogram nor MRl show signs of free silicone
within the breast parenchyma, making extracapsular
rupture unlikely. The breast parenchyma should be
studied carefully on all MRl images obtained to search
for free silicone, particularly when intracapsular
implant rupture is identified.
• Intact implant with radial folds: Radial folds are
infoldings of the intact silicone shell, generally seen on
MRl as straight, hypointense, double thickness lines,
originating at the fibrous capsule and ending blindly in
the silicone gel. Occasionally they appear angular or
curvilinear. The lines seen centrally in the case illustrated
do not correspond to radial folds, making this diagnosis
unlikely.
• Breast carcinoma: Localized breast pain is only very
infrequently associated with breast carcinoma.
However, on any breast imaging examination (whetller
the study is indicated for screening or for prosthesis
evaluation) , the breast parenchyma must be evaluated
carefully for signs of occult carcinoma. Large silicone
implants are identified by both modalities in this case,
which can obscure lesions at mammography.
Carcinoma is unlikely in this case because no mass or
other parenchymal abnormality is identified.
+ DIAGNOSIS: Intracapsular rupture of the silicone
breast prosthesis.
+ KEY FACTS
CLINICAL
• Implantable silicone prostheses have been in use since
1 962 for breast augmentation or breast reconstruction
following subcutaneous or modified radical mastectomy.
• Silicone, saline, or double-lumen silicone and saline
implants have been used most commonly and can be
placed in subglandular or submuscular positions.
• Early complications of silicone prostheses include hemorrhage
or infection in the postoperative period.
Sonography is useful for detecting these peri prosthetic
fluid collections. CT and MRl are less frequently used
for this purpose.
• Late complications of breast prostheses include capsular
contracture, rupture, migration, and rarely, extrusion
of the implant.
103
• Silicone implants were initially inlplicated in causing
autoimmune diseases, prompting the Food and Drug
Administration to limit their use. Subsequent studies
have not confirmed an association between silicone
and autoimmWle diseases.
• Most of tlle late complications of silicone prostheses
are best evaluated by physical examination. However,
inlaging studies are often necessary to detect implant
rupture.
RADIOLOGIC
• Mammography: Manlmograms have high specificity in
evaluating implant integrity, but sensitivity is low
because intracapsular rupture is frequently not detected
by mammography.
• Reliable signs of implant rupture at mammography
include free silicone within the breast parenchyma,
irregular or large smooth protrusions of the silicone
implant, and streaming of silicone away from the body
of the implant.
• Sonography: Sonographic findings of implant rupture
include the "snowstorm" sign ( an echodense column
located at the site of extracapsular silicone that
obscures underlying structures) , tlle "stepladder" sign
( echogenic parallel lines resembling a stepladder within
the implant, corresponding to the collapsed silicone
shell ) , and the presence of anechoic nodules with
echogenic back wall and echogenic reverberation, corresponding
to free silicone globules in the breast
parenchyma.
• MRl: Intracapsular rupture ( ruptured implant with silicone
contained within the surrounding fibrous capsule)
is best detected by M Rl , where the "linguine"
sign corresponds to the collapsed silicone shell.
Extracapsular silicone (gel extravasation into the breast
tissue) can also be detected by MRl as parenchymal
masses that have signal intensities paralleling those of
the implant on T2-weighted fast spin-echo images
(with and without water suppression) and on T 1 -
weighted images. These sequences allow differentiation
between silicone and other breast masses.

Front 51

A 28-year-old man presents with odynophagia.

Back 51

DIFFERENTIAL DIAGNOSIS
• Gastroesophageal reflux disease: This is the most common
cause of esophageal ulceration, and such a large
proximal ulcer raises the possibility of Barrett's change.
• Infectious esophagitis: Cytomegalovirus (CMV)
should be suspected in the immunocompromised
patient. The human immunodeficiency virus ( HIV)
itself can also result in giant esophageal ulcers.
• Medication-induced esophagitis: A history of recent
ingestion of certain medications (particularly tetracycline
antibiotics) would be relevant.
• Radiation esophagitis: Close anatomic relationship of
the area of ulceration to the portal of radiation therapy
would be relevant.
+ DIAGNOSIS: Cytomegalovirus esophagitis.
+ KEY FACTS
CLINICAL
• CMV is a member of the herpesvirus group. It causes
opportunistic esophagitis in patients with acquired
immunodeficiency syndrome (AIDS) and only rarely in
other immunocompromised patients.
• Patients usually present with odynophagia, which may
be severe. On endoscopy, ulcerative esophagitis is seen
with lesions that may be shallow or deep. It is impossible
to differentiate this disorder from other viral
esophagi tides, including involvement by the HIV itself.
• Diagnosis is made from endoscopic brushings or biopsy
specimens from the base of ulcers, by detection of
characteristic intranuclear inclusion bodies in endothe-
107
lial cells or fibroblasts, or by positive viral cultures.
Histologic findings are required to differentiate CMV
from herpetic esophagitis. HIV ulcers may respond to
the administration of steroids, but CMV esophagitis
requires antiviral agents such as ganciclovir.
RADIOLOGIC
• CMV esophagitis may appear as discrete, small, superficial
ulcers similar to those of herpes. Occasionally, a
nonspecific esophagitis with nodular thickened folds
only is seen, which may simulate reflux esophagitis.
• Giant, flat, single or multiple ulcers, often with a thin
radiolucent rim of edematous mucosa, are very suggestive
of CMV esophagitis. These ulcers may be several
centimeters in length and appear ovoid because of the
limited diameter of the esophagus.
• HIV ulcers may have an identical radiologic appearance,
requiring endoscopy and biopsy for culture and
histologic examination to make a definitive diagnosis
before appropriate treatment can commence.
• Candida esophagitis is characterized by longitudinally
orientated, small, plaque-like filling defects. Severe disease
appears as extensive, confluent, large plaques, giving
the mucosa a "shaggy" pattern. These patterns are
not typical for CMV, allowing radiologic differentiation.
+ SUGGESTED READING
Balthazar EJ, Megibow AJ, Hulnick D, et al. Cytomegalovirus
esophagitis in AIDS: Radiographic features in 16 patients. AJR
Am J Roentgenol 1987; 1 49:9 1 9-92 3 .
Sor S, Levine M S , Kowalski TE, e t a l . Giant ulcers o f the esophagus
in patients with human immunodeficiency virus: Clinical, radio
ographic and pathologic findings. Radiology 1995 ; 1 94:447-45 1 .

Front 52

A 5 5-year-old man presents with dysphagia.

Back 52

DIFFERENTIAL DIAGNOSIS
• Intramural pseudodiverticulosis: The finding of
multiple flask-shaped collections of barium, oriented
almost perpendicular to the long axis of the esophagus,
is characteristic of this condition. Not all of the pseudodiverticula
show a clear communication with the
esophageal lumen.
• Esophagitis: Features may include fold thickening,
mucosal nodularity, an irregular mucosal contour, and
focal erosions or ulcers. Ulcers can usually be seen to
communicate clearly with the esophageal lumen, whereas
in this case, some of the barium collections do not communicate.
There are no plaque-like filling defects, as may
be seen with Candida and other causes of esophagitis.
• True esophageal diverticula: These are larger and less
numerous than pseudodiverticula.
• DIAGNOSIS: Esophageal intramural pseudodiverticula.
KEY FACTS
CLINICAL
• Esophageal intramural pseudodiverticula is caused by
dilated excretory ducts of the deep esophageal mucous
glands, due to chronic inflammation. It is usually a
sequela of chronic reflux esophagitis. Secondary infection
with Candida is a common associated finding,
but it is not considered a causal factor.
• Esophageal intramural pseudodiverticula most commonly
occurs in elderly patients, with a slight male
predominance. In as many as 90% of cases, there is an
associated stricture. The most common presenting
109
symptom is dysphagia, due to the associated stricture,
and management is directed at treating the stricture.
• Esophageal intramural pseudodiverticula occurs in
approximately 0.1 % of patients undergoing barium
esophagography, with an increased prevalence in
patients with esophageal cancer (4.5%).
RADIOLOGIC
• Single-contrast barium examination with low-density
barium, which more readily enters the gland ducts, is
more sensitive than a double-contrast technique with
high-density barium for detecting intramural pseudodiverticula.
Endoscopy is relatively insensitive because it
is difficult to visualize the tiny duct orifices.
• The characteristic appearance is that of numerous small
( 1 to 4 mm), flask-shaped outpouchings from the
esophagus. The tiny necks may not fill completely,
resulting in an apparent lack of communication with
the esophageal lumen.
• Distribution is more often segmental than diffuse.
Pseudodiverticula may occur at, above, or below the
level of a stricture .
• Strictures associated with intramural pseudodiverticula
should be evaluated carefully for evidence of malignancy.
• SUGGESTED READING
Levine MS, Moolten DN, Herlinger H, et al. Esophageal intramural
pseudodiverticulosis: A re-evaluation. AJR Am J Roentgenol
1986; 1 47 : 1 1 65-1 1 70.
Plavsic BN, Chen MYM, Gelfand DW, et al. I ntramural pseudodivertic
ulosis of the esophagus detected on barium esophagograms:
I ncreased prevalence in patients with esophageal carcinoma. AJR
Am J RoentgenoI 1 995 ; 1 6 5 : 1 38 1-1 385.
Sabanathan S, Salama FD, Morgan WE. Esophageal intramural pseudodiverticulosis.
Thorax 1 98 5 ;40:849-8 57.

Front 53

A 57-year-old man presents with a long history of heartburn and gradual onset of
dysphagia.

Back 53

DIFFERENTIAL DIAGNOSIS
• Peptic stricture: Peptic strictures are nearly always
located in the distal esophagus, making this diagnosis
unlikely. There is, however, an overlap in the appearance
of peptic strictures and Barrett's esophagus.
• Caustic ingestion: A caustic stricture could have this
appearance. In this scenario, clinical history would be
the key to the diagnosis.
• Mediastinal radiation: While radiation strictures may
be long and smooth, as in this case, clinical history and
port-limited changes should be apparent in the mediastinum
and pulmonary parenchyma. With radiation
strictures, there is often displacement of both walls of
the esophagus.
• Barrett's esophagus: This is the most likely diagnosis
given the ulcer and the length and mid-esophageal
location of the stricture.
• Esophageal carcinoma: It is uncommon for esophageal
carcinoma to present with a smooth stricture.
+ DIAGNOSIS: Barrett's esophagus with a stricture
and esophageal ulcer.
+ KEY FACTS
CLINICAL
• Barrett's esophagus represents columnar metaplasia of
the squamous mucosa of the esophagus, associated
with gastroesophageal reflux and esophagitis.
• Barrett's is a premalignant condition, placing the patient
at risk for esophageal carcinoma. Prevalence of adenocarcinoma
in this population is approximately 1 5%.
111
• Of patients with Barrett's esophagus, 20% to 40% are
asymptomatic.
• Approximately 1 0% of patients with chronic reflux
esophagitis also have Barrett's esophagus.
RADIOLOGIC
• The classic fmdings of Barrett's esophagus include a
high esophageal stricture with or without an associated
ulcer. However, the classic findings are relatively
uncommon. Patients with Barrett's esophagus may
have an unremarkable esophagram or may have a stricture
in the distal esophagus, giving the appearance of a
peptic stricture .
• As in this case, the stricture may be long and smooth
or web-like.
• On double-contrast esophagography, a reticular pattern
may be present in the region of the columnar
metaplasia that may resemble the area gastricae found
in the stomach.
• Radiographic findings are neither sensitive nor specific
for this condition. Therefore, endoscopy and biopsy
are the procedures of choice to diagnose and follow
these patients.
+ SUGGESTED READING
Levine MS. Gastroesophageal Reflux Disease. In RM Gore, MS
Levine, r Laufer (eds), Textbook of Gastrointestinal Radiology.
Philadelphia: Saunders, 1994;360-384.
Levine MS, Caroline DF, Thompson JJ, et al. Adenocarcinoma of
the esophagus: Relationship to Barrett mucosa. Radiology
1 984; 1 50:305-309.
Levine MS, Kressel HY, Caroline OF, et al. Barrett's esophagus:
Reticular pattern of the mucosa. Radiology 1983; 1 47:663-667.

Front 54

A 47-year-old woman complains of dysphagia with solid food.

Back 54

DIFFERENTIAL DIAGNOSIS
• Primary esophageal carcinoma: This is the most
common cause of an intrinsic esophageal mass lesion.
• Leiomyosarcoma: Leiomyosarcomas may be large
tumors, but they tend to be predominantly intramural.
• Lymphoma: The absence of significant mediastinal lymphadenopathy
makes esophageal lymphoma unusual.
• Spindle cell carcinoma: This rare tumor, commonly
known as carcinosarcoma, usually manifests as a large
polypoid tumor in the distal esophagus.
• Intramural hematoma: A history of bleeding, coagulation
disorder, or anticoagulant therapy would be relevant
to this diagnosis.
+ DIAGNOSIS: Esophageal lymphoma.
+ KEY FACTS
CLINICAL
• Esophageal lymphoma is a rare condition, seen in only
1 % to 2% of cases of gastrointestinal lymphoma.
• It usually occurs in the presence of disseminated disease,
particularly lymphomatous mediastinal node
involvement. Patients usually present with dysphagia
due to esophageal narrowing or obstruction by a mass.
It is frequently asymptomatic and occasionally presents
with bleeding.
• Endoscopic biopsy is frequently negative due to the
submucosal location of the tumor.
113
• The tumor may be complicated by perforation into the
mediastinum, a bronchus, or the trachea.
RADIOLOGIC
• Intrinsic lymphoma of the esophagus may have a variable,
but malignant appearance, including a polypoid,
ulcerative, or infiltrative mass.
• Less frequent manifestations include numerous submucosal
nodules mimicking multiple leiomyomas or
esophageal varices if confluent.
• Lymphoma arising in mediastinal lymph nodes and
involving the esophagus appears initially as smooth
extrinsic indentation, but with progression and invasion,
will result in irregularity of the esophageal contour
and eventual narrowing.
• Gastric lymphoma invading up into the esophagus may
result in an achalasia-like picture, and careful examination
of the gastric cardia is required to detect the mass lesion.
+ SUGGESTED READING
DolO T, Hamada S, Murayama H, et aI. Primary malignant lymphoma
of the esophagus. Endoscopy 1984; 1 6 : 1 89-192.
Levine MS, Sunshine AG, Reynolds Je, et aI. Diffuse nodularity in
esophageal lymphoma. AJR Am J Roentgenol 1 98 5 ; 1 4 5 :
1 2 1 8-1 220.
Zornoza J, Dodd GD. Lymphoma of the gastrointestinal tract.
Scmin Roentgenol 1980; 1 5 :272-287.

Front 55

A 22-year-old woman presents with a several-month history of dysphagia and a 25-
pound weight loss.

Back 55

DIFFERENTIAL DIAGNOSIS
• Peptic stricture: Although peptic strictures typically
cause narrowing of the distal esophagus, they are usually
smoothly marginated and relatively fixed.
• Primary achalasia: Lack of primary peristaltic activity
with smooth tapering at the gastroesophageal (GE) jwlCtion
and i.ntermittent opening of the lower esophageal
sphincter ( LES) argue for a primary motor disorder of
the esophagus. The age of the patient and lack of an
obstructing or infiltrating mass favors primary achalasia.
• Secondary achalasia due to an intrinsic or extrinsic
neoplasm: The age of the patient, duration of symptoms,
and lack of a mass on imaging studies rules this
entity out.
• Complicated scleroderma: Narrowing of the distal
esophagus in complicated scleroderma i.s the result of a
patulous LES with free GE reflux, eventually causing a
peptic stricture. The chest CT usually reveals normal
lung bases.
• Chagas disease: TillS protozoal infection, which
involves the myenteric plexus, results in a motor disorder
of the esophagus similar to achalasia.
DIAGNOSIS: Primary achalasia.
+ KEY FACTS
CLINICAL
• Achalasia is a primary motility disorder of the esophagus
characterized by aperistalsis in the distal two-thirds
of the esophagus and failure of the LES to relax.
• The etiology is unknown, but it is thought to be neurogenic
in origin . Pathologic specimens reveal a
115
decrease in the number of ganglion cells in Auerbach's
myenteric plexus.
• Primary achalasia results in a slowly progressive dysphagia
with both solids and liquids that may develop
over many months or years. The patient may be able
to modifY dietary needs with smaller, frequent meals
and, as a result, present without any weight loss
despite severe dysphagia.
• Odynophagia and chest pain are much less common
symptoms.
• Regurgitation may lead to choking and coughing and
even to aspiration and pneumonitis.
RADIOLOGIC
• Fluoroscopic examination of esophageal motility will
identifY characteristic absence of the primary peristaltic
wave in the distal two-thirds of the esophagus.
• The esophagus eventually dilates, with distal tapering
( bird-beak or rat-tail appearance) at the GE junction.
• An important cause of this radiologic appearance is
pseudo achalasia due to malignancy. This typically
occurs in an older age group ( > 5 0 years) with a shorter
duration « 6 m onths) of dysphagia. This is most commonly
due to a carcinoma of the gastric cardia or fundus
with invasion of the distal esophagus. This may also
be due to actual infiltration of the myenteric plexus or
to high-grade obstruction at the GE junction.
+ SUGGESTED READING
Kahrilas PI, Kishk SM, Helm ]F, et al. Comparison of pseudoachalasia
and achalasia. Am J Med 1987;82 :439-446.
Laufer 1. Motor Disorders of the Esophagus. In MS Levine (ed),
Radiology of the Esophagus. Philadelphia: Saunders,
1 989;229-246.

Front 56

A 34-year-old man presents with crampy abdominal pain and diarrhea.

Back 56

DIFFERENTIAL DIAGNOSIS
• Erosive gastritis: Varioliform erosions may result from
ingestion of alcohol, aspirin, and nonsteroidal anti-inflanlmatory
drugs. Other causes include ischemia, stress, and
trauma. Duodenal involvement would be unusual.
• Infectious gastritis: Helicobacter pylori is important in
antral gastritis. Features include fold thickening, ulceration,
and sometimes antral narrowing and duodenal
ulceration. CMV infection occurs in AIDS and other
immunocompromised patients. Nonspecific findings
include fold thickening, erosions or ulcers, and antral
narrowing. Pneumocystis carinii pneumonia, herpesvirus,
toxoplasmosis, and cryptosporidiosis may also have
similar findings.
• Granulomatous disease: Gastroduodenal Crohn's disease
typically has antral aphthous lesions, duodenal
ulcers, and tapering of the antrum and pylorus, resulting
in a "ram's horn" configuration. Sarcoidosis,
tuberculosis (TB), and syphilis may have similar features,
with antral ulcers progressing to fibrosis and
scarring.
• Zollinger-Ellison syndrome (ZES): Although the presence
of postbulbar ulcers suggests ZES, there should also
be gastric fold thickening and increased fluid.
• Eosinophilic gastritis: Although eosinophilic gastritis
typically involves the gastric antrum and proximal
small bowel, nodularity and fold thickening are more
. common features. Gastric erosions are atypical, and
duodenal ulcers are rare.
• Scirrhous carcinoma: This entity typically causes a
smooth, funnel-shaped narrowing of the antrum.
Irregular fold thickening and ulceration may also
occur. It is unlikely to cross the pylorus.
DIAGNOSIS: Gastroduodenal Crohn's disease.
KEY FACTS
CLINICAL
117
• Gastroduodenal Crohn's is almost always associated
with concomitant ileocecal disease but rarely may
occur before the development of more distal disease.
• Although it may be asymptomatic in the early stages, pain,
nausea, vomiting, and weight loss are common in advanced
stages. Gastric outlet obstruction may even occur.
RADIOLOGIC
• Gastric Crohn's disease typically involves the antrum
and sometimes the body, but fundal involvement is
uncommon. Duodenal disease usually occurs in association
with antral involvement, but isolated duodenal
disease is possible.
• Aphthous lesions may appear as punctate or slit-like collections
of barium with a lucent halo, indistinguishable
from varioliform ulcers of erosive gastritis. Larger ulcers,
mucosal effacement, or cobblestoning may also occur.
• Fibrosis may result in a funnel-shaped or ram's horn
antrum. A pseudo-Billroth I sign is due to scarring of the
antrum and duodenum with obliteration of tile pylorus.
• Duodenal ulcers may be single or multiple. Duodenal
strictures are usually postbulbar, smoothly tapering,
and may be multiple. Skip lesions may occur.
• Asymmetric or eccentric scarring in the duodenum
may result in pseudodiverticula.
• SUGGESTED READING
Farman J, Faegenburg D, Dallemand S, et aI. Crohn's disease of the
stomach: The "rams-horn" sign. AJR Am J Roentgenol 1 975;
1 23 :242-2 5 l .
Levine M . Crohn's disease of the upper gastrointestinal tract. Radiol
Clin North Am 1987;2 5 : 79-9 l .
Nelson SW. Some interesting and unusual manifestations of Crohn's
disease of the stomach, duodenum and small intestine. AJR Am J
Roentgenol 1 969; 1 07:86- 1 0 1 .

Front 57

A 40-year-old man presents with dyspepsia. He is taking nonsteroidal antiinflammatory
agents for arthritis.

Back 57

DIFFERENTIAL DIAGNOSIS
• Erosive gastritis: This is the most likely diagnosis
given the history and distribution of lesions.
• Crohn's disease: Gastric involvement usually occurs in
the presence of advanced disease elsewhere, particularly
the terminal ileum.
• Viral infection: This type of gastritis usually occurs in
patients with immunodeficiency.
• Ulcerated submucosal masses: With these masses, the
central ulcer, as well as the surrounding mass, tends to
be larger than in this case.
• Barium precipitates: These artifacts do not have a
radiolucent halo and will move when the patient is
repositioned, either by the effect of gravity or the
flowing pool of liquid barium.
+ DIAGNOSIS: Erosive gastritis.
+ KEY FACTS
CLINICAL
• These erosions are superficial epithelial defects that do
not extend beyond the muscularis mucosa.
• Drugs are an identifiable cause of erosive gastritis,
including aspirin, nonsteroidal anti-inflammatory
drugs, steroids, and alcohol .
• In half the cases, no cause is identified. These cases are
probably a manifestation of peptic disease.
119
• Other causes of gastric erosions include Crohn's disease,
viral infection, and iatrogenic trauma ( gastric
catheters and endoscopic therapy) .
RADIOLOGIC
• Erosions appear as very shallow collections of barium .
These are always small and may have a variety of shapes,
including row1d, polygonal, linear, and punctate.
• There is associated nodular thickening of the rugal folds,
and the erosions are aligned along the crest of these
folds. On barium studies, the abnormal folds are often
more easily visualized than the erosions themselves, and
they may persist after the erosions have healed.
• Because the lesions are shallow, the changes are subtle.
Disease on the more dependent posterior wall is visualized
more readily by manipulating a thin film of barium
into the region to opacify the erosions and the spaces
between the folds. Disease on the anterior wall is visualized
best in the prone position using compression.
+ SUGGESTED READING
Catalano D, Pagliari U. Gastroduodenal erosions: Radiological findings.
Gastrointest Radiol 1982;7:235-240.
Laufer I, Hamilton ], Mullens JE. Demonstration of superficial gastric
erosions by double contrast radiography. Gastroenterology
1 975;68 : 387-39 1 .

Front 58

A 50-year-old woman presents with epigastric pain for several months.

Back 58

DIFFERENTIAL DIAGNOSIS
• Gastric ulcer: An ulcer would have a central niche of
barium and a surrounding mound of edema. However,
such mounds usually have peripheral indistinct or fading
borders, in contrast to the sharp outline of this lesion.
• Leiomyoma: This uncommon benign tumor could
have this appearance, as would other benign mesenchymal
tumors.
• Ectopic pancreatic rest: This is the most likely diagnosis
by virtue of its benign submucosal appearance
with central umbilication, as well as its location which
is typical .
• "Bull's eye" metastases: These can appear with
metastatic melanoma, lymphoma, or Kaposi's sarcoma.
However, they are almost always multiple and occur in
the context of disseminated disease elsewhere .
+ DIAGNOSIS: Ectopic pancreatic rest.
+ KEY FACTS
CLINICAL
• Ectopic pancreas occurs due to an anomaly in embryologic
development where a fragment of migrating
pancreatic precursor becomes implanted in the intestinal
wall. Histologically, all normal pancreatic elements
are present but show a disorganized arrangement.
• The majority of pancreatic rests occur in the stomach
( 80%) . They are also found in the duodenum and
proximal jejunum. They have also been reported in the
gallbladder, bile ducts, liver, spleen, appendix,
Meckel's diverticulum, omentum, mesentery, and
mediastinum.
121
• These lesions are usually asymptomatic and discovery
of such should not be accepted as the cause of a
patient's symptoms.
• Rarely, enzyme production results in epigastric pain
and intestinal bleeding. These lesions have also been
reported to cause gastric outlet obstruction due to
their strategic position near the pylorus.
RADIOLOGIC
• The lesion appears as a smooth, broad-based, solitary,
submucosal mass.
• The most common location is along the distal greater
curvature of the stomach, several centimeters from the
pylorus.
• The central umbilication or dimple is thought to represent
the orifice of the duct in this rest. It usually
measures 1 to 5 mm in diameter and 5 to 10 mm in
depth. Rarely, a rudimentary ductal system is sufficiently
filled by contrast material to be visualized.
+ SUGGESTED READING
Levine MS. Benign Tumors of the Stomach and Duodenum . In RM
Gore, MS Levine, I Laufer (eds), Textbook of Gastrointestinal
Radiology. Philadelphia: Saunders, 1994:649-65 1 .
Thoeni RF, Gedgaudas RK. Ectopic pancreas: Usual and unusual
features. Gastrointest Radiol 1 980;5:37-42.

Front 59

A 44-year-old woman with stage IV breast carcinoma is status post bone marrow
transplant and high-dose chemotherapy.

Back 59

DIFFERENTIAL DIAGNOSIS
• Diffusely infiltrating (scirrhous) adenocarcinoma of
the stomach: The radiographic appearance of diffuse
gastric wall thickening in a poorly distensible stomach
is radiographically indistinguishable from diffusely infiltrating
metastatic disease .
• Diffusely infiltrating metastatic disease: Given the
patient's clinical history, this is the most likely diagnosis.
• Lymphoma: Diffuse gastric involvement with lymphoma
may give this appearance. There is no regional
abdominal or retroperitoneal lymphadenopathy. The
spleen is normal size. When there is gastric involvement
of lymphoma, it may cross the pylorus to
involve the duodenum. The duodenum is normal in
this patient.
• Infectious/inflammatory gastritis: Crohn's disease,
chromc gastric ulcer disease with spasm, eosinophilic
gastritis, sarcoidosis, tuberculosis ( TB ) , and brucellosis
are other causes of gastric wall thickemng and luminal
narrowing. These more typically involve the gastric
antrum.
• Physical/chemical gastritis: Corrosive gastritis,
postradiation injury, and hepatic arterial chemoinfusion
are other less common causes of this appearance .
+ DIAGNOSIS: Diffusely infiltrating metastatic
breast carcinoma to the stomach (linitis plastica
appearance).
+ KEY FACTS
CLINICAL
• Metastatic disease to the stomach is not uncommon.
The most common organs of origin include malignant
melanoma, breast, lung, colon, prostate, leukemia, and
secondary lymphoma.
123
• The pattern of gastric involvement is variable. Solitary
mass: 50%; multiple nodules: 30%; and linitis plastica
(diffusely infiltrating): 20%. The diffusely infiltrating
variety is most commonly seen in breast carcinoma.
• Patients often present with early satiety, nausea, and
vomiting. This patient could not tolerate oral contrast
material due to severe nausea and vomiting.
RADIOLOGIC
• The differential diagnosis for diffuse gastric wall thickening
with a poorly distensible lumen is fairly extensive.
Malignant causes head the list and are most commonly
due to the diffusely infiltrating variety of adenocarcinoma
of the stomach, metastatic disease, or nonHodgkin's
lymphoma .
• Other causes o f this radiographic appearance include
inflammation secondary to chromc gastritis, Crolm's
disease giving a pseudo-Billroth I appearance,
eosinophilic gastritis, and sarcoidosis.
• Infectious etiologies include TB and brucellosis. TB
may be radiographically indistinguishable from
Crohn's disease as a cause of antral narrowing.
• Physical/chemical causes are most commonly due to
corrosive gastritis and radiation therapy.
+ SUGGESTED READING
Eisenberg RL. Gastrointestinal Radiology: A Pattern Approach (2nd
ed). Philadelphia: Lippincott, 1 990;205-222.
Jaffe M . Metastatic involvement of the stomach secondary to breast
carcinoma. AJR Am J RoentgenoI 1975 ; 1 2 3 : 5 1 2-52 1 .
Levine MS, Kong V, Rubesin SE, et al. Scirrhous carcinoma of the
stomach: Radiologic and endoscopic diagnosis. Radiology
1990; 1 75 : 1 5 1-1 54.
Levine MS, Megibow AI. Stomach and Duodenum: Carcinoma. In
RM Gore, MS Levine, I Laufer (eds), Textbook of
Gastrointestinal Radiology (voU ). Philadelphia: Saunders,
1 994;660-683.

Front 60

A 38 -year-old woman presents with nausea, vomiting, abdominal pain, and weight
loss. Her serum amylase and lipase levels were elevated.

Back 60

DIFFERENTIAL DIAGNOSIS
• Hypertrophic gastritis: This is a condition characterized
by glandular hyperplasia and increased acid secretion,
with thickened folds predominantly in the fundus
and body of the stomach. The majority of cases have
an associated peptic ulcer. The focal nature of fold
thickening in this case makes the diagnosis unlikely.
• Menetriers disease: The gastric folds are usually more
thickened tllan in hypertrophic gastritis, and there is
relative sparing of the antrum . There may be mass-like
fold thickening, although the abnormality is unlikely
to be as focal as in this case. The folds in Menetriers
disease also tend to follow the distribution of normal
rugae, and there are increased secretions.
• Lymphoma: Gastric lymphoma may cause irregular or
lobulated fold thickening due to submucosal infiltration
or multiple submucosal masses. Submucosal infiltration
by carcinoma may also cause this appearance.
• Varices: Gastric varices typically appear as multiple,
smooth, lobulated, filling defects that tend to change in
size and shape on fluoroscopy. The serpentine appearance
of the folds in this case favors this diagnosis.
DIAGNOSIS: Isolated gastric varices.
+ KEY FACTS
CLINICAL
• Gastric varices are less likely to bleed than esophageal
varices. However, they may present with low-grade
bleeding or massive hematemesis.
• Gastric varices are usually associated with esophageal
varices and are secondary to cirrhosis with portal
hypertension.
• Isolated gastric varices may be caused by splenic vein
wombosis, resulting in shunting of blood from the
125
spleen wough the short gastric veins to the fundus,
where tlley anastomose with branches of the coronary
vein and esophageal plexus. With normal portal venous
pressure, tlle blood can drain via the coronary vein into
the portal vein without producing esophageal varices.
RADIOLOGIC
• Gastric varices are characteristically multiple, lobulated,
serpentine masses, but they may produce a single polypoid
mass in the fundus.
• Gastric varices may be obscured on barium stuclies by
the normal overlying gastric rugae. Gastric varices are
seen radiographically in <50% of patients with uphill
esophageal varices.
• It is important to exanline the distal esophagus in
patients with gastric varices for identification of
esophageal varices.
• A double-contrast barium technique is considered
more reliable than a single-contrast technique for identification
of varices.
• The isolated gastric varices in this patient were due to
splenic vein occlusion secondary to pancreatitis.
Because portal hypertension is much more common
than splenic vein occlusion, most patients with isolated
gastric varices are found to have portal hypertension
as the underlying cause.
+ SUGGESTED READING
Evans JA, Delany F. Gastric varices. Radiology 195 3;60:46-5 l .
Levine MS, Kieu K, Rubesin SE, e t al. Isolated gastric varices:
Splenic vein obstruction or portal hypertension? Gastrointesr
RadioI 1990; 1 5 : 1 88-192.
MuhJeraler C, Gerlock J , Goncharenko V, er al . Gastric varices secondary
to splenic vein occlusion : Radiographic diagnosis and
clinical significance. Radiology 1 979 ; 1 32 : 593-598.

Front 61

A 33-year-old man presents with dyspepsia. He has had many hospital admissions
since childhood for recurrent pulmonary infections.

Back 61

DIFFERENTIAL DIAGNOSIS
• Peptic duodenitis: This is a common condition that
may coexist with other pathologic conditions causing
the pulmonary changes, or may have occurred due to
steroid or other medication therapy used to treat the
lung condition.
• Cystic fibrosis: This is the most likely diagnosis as it
would explain both the pulmonary and duodenal
changes. The patient's age, however, is rather
advanced for this condition.
• Scleroderma: I ntestinal fibrosis from scleroderma may
produce this duodenal pattern and may also be associated
with pulmonary fibrosis.
• Tuberculosis (TB): TB would explain the upper lobe
fibrotic changes. Duodenal involvement, however, is
rare and usually results i n strictures and fistulae.
• Pancreatitis and other periduodenal inflammatory
processes: These conditions may cause the nonspecific
duodenal changes but do not adequately explain the
pulmonary abnormalities.
+ DIAGNOSIS: Cystic fibrosis.
+ KEY FACTS
CLINICAL
• Cystic fibrosis occurs in 1 in 2 ,000 births, predominantly
in whites. Clinical and radiologic manifestations
occur due to viscous secretions.
• The diagnosis is usually made clinically in infancy, but
in about 2% of patients, symptoms may not manifest
127
until after 18 years of age. Older patients present with
hepatobiliary or gastrointestinal tract symptoms.
• With improvements in pulmonary care, increasing
numbers of cystic fibrosis patients are surviving into
adulthood.
• A majority ( 8 5% ) of patients will have malabsorption
due to impaired exocrine pancreatic secretions. These
secretions are viscous, low in bicarbonates, and low i n
enzymes.
RADIOLOGIC
• Duodenal changes are seen in 60% to 80% of patients
and consist of fold thickening, mucosal noduiarity, fold
flattening, luminal dilatation, smudging, and poor definition
of the mucosal fold pattern. These changes are
usually confined to the first and second portions of the
duodenum and occur without ulcerations.
• In the small bowel, blobs of mucous result in a network
pattern of curved lines, predominantly involving
the distal small bowel.
• Intestinal obstruction and impaction can occur during
and after childhood.
• Pancreatic calcification may be evident on plain
radiographs.
+ SUGGESTED READING
Phelan MS, Fine DR, Zentler-Mlmro L, et al. Radiographic abnormalities
of the duodenum in cystic fibrosis. elin Radiol
1983;34 : 5 73-577.
Taussig LM, Saldino RM, di Sant'Agnese PA. Radiographic abnormalities
of the duodenum and small bowel in cystic fibrosis of the
pancreas (mucoviscidosis). Pediatr Radiol 1973; 1 06: 369-376.

Front 62

A 3 5-year-old man presents with several months of intermittent vomiting.

Back 62

DIFFERENTIAL DIAGNOSIS
• Benign duodenal polyp with intussusception: A
solitary duodenal polyp is usually hyperplastic or adenomatous.
• Polyposis syndrome: These polyps are either adenomas
or hamartomas. Characteristically, there will be
other polyps throughout the intestinal tract.
• Benign mesenchymal tumor: Leiomyoma and lipoma
are the most common of this group. These tumors
are usually submucosal but may demonstrate central
ulceration.
• Leiomyosarcoma: This usually occurs as a large, lobulated,
submucosal mass, and ulceration or cavitation is
common.
• Duodenal carcinoma: This may present as a polypoid
mass but usually has more aggressive features, such as
infiltration and annular narrowing.
+ DIAGNOSIS: Leiomyosarcoma with
intussusception.
+ KEY FACTS
CLINICAL
• Leiomyosarcomas represent about 1 0% of duodenal
malignant tumors. These tumors are typically slow
growing; therefore patients may remain asymptomatic
for a long period of time. Clinical presentations
129
include gastrointestinal bleeding and anemia, abdominal
pain, epigastric mass, weight loss, and jaundice.
• These tumors are of smooth muscle origin, and they
vary in clinical and histologic degrees of aggression
from nearly benign to highly invasive .
• The tumor spreads by direct invasion of adjacent structures
and metastases to the Liver.
• Aggressive resection is indicated in surgical candidates.
RADIOLOGIC
• The majority of duodenal leiomyosarcomas (80%) occur
in the descending (D2) and transverse segments (D3).
• On barium studies, they usually appear as submucosal
masses, usually with ulceration or even cavitation. They
may enlarge to several centimeters in diameter but still
remain nonobstructive .
• Some tumors have a predominantly exoenteric growth
pattern . These will appear on barium studies as extrinsic
lesions, more suggestive of a mass arising from an
adjacent structure, such as the pancreas. The full
extent of such tumors is assessed best by CT.
• Areas of necrosis result in low attenuation on CT, usually
within the central portion of the tumor.
+ SUGGESTED READING
Kanematsu M, Imada T, Iianuluma G, et al. Leiomyosarcoma of the
duodenum. Gastrointest Radiol 1 99 1 ; 1 6 : 1 09-1 1 2 .
Pujari B D , Deadhare S G . Leiomyosarcoma o f the duodenum. lnt
Surg 1976;6 1 :2 37-238

Front 63

A 75-year-old man has persistent nausea and vomiting since an abdominal aortic
aneurysm repair 1 month previously.

Back 63

DIFFERENTIAL DIAGNOSIS
• Mesenteric root syndrome: This is the appropriate
clinical scenario for this condition, and the point of
narrowing does appear to correspond to the location
at which the duodenum passes between the superior
mesenteric artery and the aorta.
• Duodenal obstruction by adhesions: The transverse
duodenum lies in close proximity to the site of major
surgery in this case. Extensive dissection of the
retroperitoneal tissues is required for this procedure,
and a dense inflammatory reaction may result in adhesions
and duodenal obstruction.
• Intramural hematoma: Hemorrhage should always be
considered in the postoperative patient. The absence of
a para-aortic or paraduodenal soft tissue mass or fluid
collection excludes this possibility.
• Duodenal malignancy: Duodenal carcinoma or invasion
of the duodenum from carcinoma of an adjacent
organ may present as a partially obstructing stricture .
The absence of a soft-tissue mass on CT scan excludes
this diagnosis.
DIAGNOSIS: Duodenal obstruction by adhesions
after abdominal aortic aneurysm repair.
+ KEY FACTS
CLINICAL
• Complications involving the gastrointestinal tract following
abdominal aortic aneurysm repair have been
reported in up to 30% of cases. Some of these complications
carry a very high mortality.
• Complications specifically involving the duodenum
include aortoduodenal fistula and resultant massive
hemorrhage, hematoma, retroperitoneal abscess, fibrosis
and adhesion, ischemic stricture, and mesenteric
root syndrome.
131
• Major aortic and retroperitoneal surgery is complicated
frequently by postoperative ileus, which may be quite
prolonged .
• An aortoduodenal fistula may present with massive
intestinal hemorrhage. An abscess would typically present
with fever and leukocytosis. The various complications
of mechanical obstruction and paralytic ileus usuaUy
present witl1 nonspecific nausea and vomiting.
RADIOLOGIC
• The location of the stricture in this case illustrates the
importance of continuing an examination of the upper
gastrointestinal tract to tl1e level of the jejunum.
• Cross-sectional imaging techniques such as CT and
ultrasound are useful in the evaluation of duodenal
strictures, particularly for detecting a mass arising from
the duodenum or one involving the duodenum from
an adjacent structure. A soft-tissue duodenal mass raises
the possibility of duodenal carcinoma or leiomyosarcoma.
Carcinoma of the pancreas, because of its close
proximity, may also involve the duodenum.
Paraduodenal fluid collections ( cysts, abscess,
hematoma, pancreatic pseudocyst) would be seen as
low attenuation on CT and hypoechoic on ultrasound.
• CT scanning is useful in this clinical scenario for
demonstrating the close proximity of tl1e point of duodenal
obstruction to the site of surgery, as well as to
demonstrate dense, adjacent inflammatory changes in
the retroperitoneum.

Front 64

A 35-year-old man presents with a 6-month history of diarrhea.

Back 64

Crohn's disease: Involvement of the terminal ileum
and distal ileum, discontinuous segments of disease,
stricture, and fistulae formation are characteristic of
Crohn's disease. The CT appearance is also typical,
with the marked mural thickening and inflammatory
change in the mesenteric fat.
• Ulcerative colitis: Ulcerative colitis can involve the
terminal ileum by backwash ileitis, but the discontinuous
involvement makes this diagnosis less likely.
Additionally, the fistula formation and inflammatory
change in the adjacent mesenteric fat are WlUSUal .
• Ischemia: The distribution of disease makes a vascular
etiology lower in the differential. Ischemic insult to
bowel more commonly involves the left colon than the
right colon, and small bowel involvement is less common.
• Neoplasms: Adenocarcinoma more commonly involves
the duodenum and proximal jejunum. Lymphoma usually
presents as polyps or large excavating lesions.
• Infection: Tuberculosis (TB ) is rare in developed
countries. Features that suggest TB rather than
Crohn's disease include greater involvement of the
cecum than the terminal ileum. The ulcers tend to be
larger than in Crohn's disease. Yersinia ileitis may also
have an appearance similar to Crohn's disease, but the
disease is self-limited and the radiographic changes
would return to normal in time.
• Other perienteric inflammatory conditions:
Appendicitis or endometriosis are differential considerations.
The involvement of a loop of distal ileum in addition
to the cecum and terminal ileum makes appendicitis
less likely. Endometriosis may cause serosal abnormality
of bowel, bu t not the strictures and fistulas seen in this
patient. Additionally, endometriosis more commonly
affects the sigmoid and transverse mesocolon.
• DIAGNOSIS: Crohn's disease.
KEY FACTS
CLINICAL
• Crohn's disease is an inflammatory bowel disease of
unknown etiology. There is a family history in approximately
40% of cases. The overall incidence is approximately
5 in 100,000. The age of onset is usually in
adolescence or young adulthood.
• Early Crohn's disease is a mucosal disorder characterized
by aphthous erosions or ulcers, which can be
detected by a barium examination or endoscopy. The
disease progresses to the submucosa and eventually
becomes transmural. Any portion of the gastrointesti-
133
nal tract can be involved, although the terminal ileum
is the most common site of disease. Extraintestinal
involvement includes uveitis, arthritis, and erythema
nodosum. The treatment includes medical suppression
of the inflammatory reaction and surgical resection.
The disease often recurs following surgical resection,
often at the anastomotic site.
RADIOLOGIC
• The radiologic diagnosis is typically made by a contrast
examination such as an upper gastrointestinal examination,
small-bowel follow-through, enteroclysis, or barium
enema. The earliest changes of Crohn's disease are
aphthous lesions or erosions, which appear as a central
fleck of barium surrounded by a translucent halo.
These initial changes occur in the mucosal lymphoid
tissue. The appearance is nonspecific and can be seen
in other inflammatory diseases.
• With progression of disease, mural thickening occurs,
often > 1 cm. The bowel wall thickening in Crohn's
disease is usually greater than that seen in ulcerative
colitis. Asymmetric or discontinuous involvement of
the gastrointestinal tract is characteristic, as opposed to
the continuous involvement by ulcerative colitis. A
typical nodular, cobblestone appearance is seen consisting
of longitudinally oriented ulcerations.
• The terminal ileum is the most common site of
involvement. Techniques to delineate the terminal
ileum include enteroclysis, peroral pneumocolon, and a
prone-angled compression view on SBFT. Strictures,
fistulae, and abscess formation are more commonly
seen in Crohn's disease than in ulcerative colitis.
• CT demonstrates the extralunlinal extent of disease. The
most common CT finding in Crohn's disease is bowel
wall thickening. Another common finding is inflammatory
change in the adjacent mesenteric fat. This mesenteric
change is seen in Crohn's disease rather than ulcerative
colitis as the former is a transmural process and the
latter is limited to the mucosa. Fibrofatty proliferation of
the mesentery and enlarged mesenteric lymph nodes are
also seen in Crohn's disease. CT is also helpful in the
diagnosis of abscess formation.

Front 65

A 6 1 -year-old woman has frequent and severe episodes of abdominal pain and
distention.

Back 65

DIFFERENTIAL DIAGNOSIS
• Mesenteric metastatic disease: Marked desmoplastic
reaction may be seen with certain metastatic tumors,
such as scirrhous gastrointestinal tract cancers and
breast cancer.
• Carcinoid tumor: This would explain the region of
mass effect, which may be due to the tumor itself
together with surrounding fibrosis. Similarly, smallbowel
loop separation represents mesenteric infiltration,
and the spiculation is due to the tumor's desmoplastic
response .
• Endometriosis: This entity is unlikely, as the patient is
postmenopausal.
• Crohn's disease: This disorder could provide an
explanation for the inflammatory mass and mesenteric
inflammation. However, the lack of fistula formation
and terminal ileal disease makes this diagnosis unlikely.
• Hemorrhage: Mesenteric and intramural hemorrhage
may occur with bleeding disorders or anticoagulant
therapy.
+ DIAGNOSIS: Carcinoid tumor.
+ KEY FACTS
CLINICAL
• Carcinoid tumors account for one-fourth of smallbowel
tumors, and the ileum is the most common site
for malignant carcinoids.
• Carcinoids arise from enterochromaffin cells and are
slow growing, but essentially all are potentially malignant.
The jejunum may remain asymptomatic for many
years. Later, symptoms suggestive of a small-bowel
lesion may occur, such as intermittent obstruction,
diarrhea, and blood loss.
135
• The tumor produces active hormones such as 5 -
hydroxytryptamine, histamine, and serotonin. These
result in the carcinoid syndrome (cutaneous flushing,
diarrhea, and bronchospasm ) in the presence of metastases
to the liver.
RADIOLOGIC
• Early tumors « 2 cm in diameter) are usually found in
the distal or terminal ileum as nonspecific smooth,
round mucosal, or submucosal masses.
• When the tumor invades through the muscularis, serotonin
is released, resulting in an intense desmoplastic
reaction. This produces fibrosis with tethering, angulation,
and spiculation of adjacent loops of bowel. This
phenomenon may be well in excess of the extent of the
tumor mass itself. Actual extension of tumor beyond
the bowel will be seen as a soft-tissue mass displacing
and surrounding adjacent bowel loops. The tumor will
also spread through the mesentery.
• On CT, a carcinoid tumor is seen as a mesenteric mass
with soft-tissue strands extending through the mesentery
toward adjacent bowel loops. Liver metastases are
usually well defined and hypervascular. They tend to
be iso- to hypoattenuating precontrast, hyperattenuating
in the hepatic arterial dominant phase, and hypoto
isoattenuating in the portal venous dominant phase.
+ SUGGESTED READING
Balthazar EJ. Carcinoid tumors of the elementary tract:
Radiographic diagnosis. Gastrointest Radiol 1978;3 :47-56.
Herlinger H, Maglinte DDT. Tumors of the Small Intestine. In H
Herlinger, DDT Maglinte (eds), Clinical Radiology of the Small
Intestine. Philadelphia: Saunders, 1989;406-409.

Front 66

A 49-year-old woman presents with crampy abdominal pain, steatorrhea, and
weight loss.

Back 66

DIFFERENTIAL DIAGNOSIS
• Sprue, tropical or nontropical (celiac disease): The
hallmark is small-bowel clilatation with segmentation of
the barium column, flocculation, fragmentation, jejunization
of ileal loops, transient nonobstructive intllSsusceptions,
and the "moulage sign" ( 50%).
• Lymphoma of small bowel: Lymphoma does not
have signs of hypersecretion or jejlmization but can
present as a diffuse small-bowel disease with nodular
fold thickening. Lymphoma can also be associated
with intussusceptions.
• Crohn's disease: This clisorder typically involves the
terminal ileum and is characterized by skip areas, transmural
disease with fistula formation, and involves the
jejunum-ileum in 1 5% to 5 5% of cases. However,
Crohn's is not associated with intussusceptions.
+ DIAGNOSIS: Nontropical sprue (celiac disease).
+ KEY FACTS
CUNICAL
• Sprue is manifested by diarrhea and steatorrhea, as well
as fatigue, weight loss, anemia, neuropathy, stomatitis,
osteomalacia, and depression.
• Nontropical sprue responds to a gluten-free diet, and
tropical sprue responds to antibiotics.
137
• The diagnosis is made by duodenal or jejunal biopsy
showing total or subtotal villous atrophy and a clinical
and histologic response to a gluten-free diet or antibiotic
regimen.
RADIOLOGIC
• The classic racliographic finclings in patients with sprue
are small-bowel dilatation, segmentation and flocculation
of barium, hypersecretion, and the "moulage sign."
• Jejunization of the ileum is the result of atrophy of
jejunal mucosal folds with an increase in ileal folds as an
adaptive response to increase functional surface area.
• Intussusceptions are seen on small-bowel series in
approximately 20% of celiac patients. Intussusceptions
can be transient and asymptomatic and are diagnosed
when there is a localized filling defect with a "coiledspring"
appearance .
+ SUGGESTED READING
Cohen MD, Lintott DJ. Transient small bowel intussusception in
adult celiac clisease. Clin Racliol 1978;29:529-534.
Eisenberg RL. Gastrointestinal Racliology. Philadelphia: Lippincott,
1983;448-4 5 l .
Rubesin SE, Herlinger H , Saul SH, et al. Adult celiac clisease and its
complications. Racliographics 1989;9: 1 045-1 065

Front 67

A 57-year-old woman presents with sudden onset of watery diarrhea, fever, and
abdominal tenderness.

Back 67

DIFFERENTIAL DIAGNOSIS
• Pseudomembranous colitis: This is the best diagnosis
because of widespread thumbprinting in the colon,
ascites, and small bowel ileus.
• Infectious colitis: Colitis with thumbprinting can be
seen with bacteria, including Salmonella and Escherichia
coli, and parasites, including Anisakis and Amoebae.
• Ischemic colitis: The distribution is atypical for
ischemia since the watershed region is located toward
the splenic flexure. However, ischemia due to a vasculitis
may not follow such vascular territories.
• Intramural hemorrhage: A history of trauma, bleeding
disorder, or anticoagulant therapy would be contributory.
• Inflammatory bowel disease: This is unlikely because
Crohn's disease is usually segmental, and ulcerative
colitis of this severity would tend to show toxic dilatation
as well.
• Lymphoma: This is unlikely because there is usually a
large cavitary mass, most often localized to the right
colon. Diffuse changes may be seen in advanced disseminated
lymphoma, although lymphadenopathy
would be expected.
+ DIAGNOSIS: Pseudomembranous colitis.
+ KEY FACTS
CLINICAL
• Pseudomembranous colitis occurs due to toxins (A and
B) liberated by Clostridium difficile, a gram-positive
organism in patients with recent exposure to either
antibiotics (most commonly clindamycin , ampicillin, or
cephalosporins, but almost all antibiotics have been
implicated) or chemotherapy ( usually methotrexate or
fluorouracil ) . Onset is usually within 2 days to 2 weeks
after introduction of the treatment but may be as late
as 8 weeks.
139
• Clinical illness ranges from mild diarrhea to fulminant
colitis with toxic megacolon and death. Fever, leukocytosis,
and abdominal pain may also occur.
• Characteristic pseudomembranes may be seen endoscopically.
However, the distal colon may appear normal in
up to 50% of patients. Visible pseudomembranes may
not have developed early in the course of the illness, and
colitis may be limited to the right colon and remain
undetected unless full colonoscopy is performed.
• The diagnosis is established by detection of the specific
toxins in the stool, but this takes 2 days to complete.
• Specific treatment is comprised of oral vancomycin or
metronidazole.
RADIOLOGIC
• The plain abdominal radiograph is normal in >60% of
patients with pseudomembranous colitis. When abnormal,
thumbprinting due to mucosal edema is visible in
over half the cases. Other manifestations include
colonic or small bowel ileus and ascites.
• Abdominal CT is more sensitive to the detection of
colonic or other manifestations of the disease, but up to
40% of patients have normal scans. CT has the advantage
of visualizing the colonic wall directly without having
to rely on the presence of luminal gas to render the
mucosal surface radiographically visible. Additional
signs include pericolonic stranding and ascites.

Front 68

A 56-year-old woman has fevers, left-lower quadrant tenderness, and an elevated
white blood cell count.

Back 68

DIFFERENTIAL DIAGNOSIS
• Diverticulitis: The CT findings and clinical history
make this the most likely diagnosis. The lack of extensive
diverticular changes should not discourage one
from making this diagnosis.
• Perforated colon cancer: Circumferential tumor infiltration
can be difficult to distinguish from diverticuJitis.
A longer segment of colonic involvement argues
against colon cancer. The saw-tooth appearance of the
lumen also favors diverticulitis.
• Crohn's disease: Mural thickening and pericolic
inflammatory changes may also be seen in Crohn's disease.
Crohn's disease typically has eccentric mural
thickening as well as skip areas of colonic and small
bowel involvement.
• Radiation colitis: There is no clinical history to support
this diagnosis. Radiation therapy to the pelvis
would likely involve the rectum as well.
• Ischemic colitis: Isolated ischemia of the sigmoid
colon would be unusual.
• DIAGNOSIS: Sigmoid diverticulitis.
+ KEY FACTS
CLINICAL
• Classic clinical features are left-lower quadrant pain,
tenderness, fever, and leukocytosis. Of patients with
diverticulosis, 1 5% to 30% will develop diverticulitis.
• Clinical management includes antibiotics for mild disease
and surgery for more severe cases. Percutaneous
abscess drainage and antibiotics can help convert
colonic surgery into a single- rather than a two-stage
procedure .
• Complications of diverticulitis include perforation,
muscular hypertrophy and obstruction, pericolic
141
abscess, and vesicocolic fistula. Most inflammatory
complications are secondary to a ruptured diverticulum
and occur in a pericolic location.
• The sigmoid colon is involved in 95%, and the cecum
in 5% of cases.
RADIOLOGIC
• Contrast enema (CE) depicts the bowel lumen, spasm,
and muscle hypertrophy, but the pericolic inflammatory
changes can only be inferred indirectly. A CE
underestimates the degree of pericolic inflammatory
changes tllat are the hallmark of acute diverticulitis .
However, CE is often valuable in differentiating diverticulitis
from colon cancer.
• The CT hallmark of acute diverticulitis is the presence
of inflan1l11atory changes in the pericolic fat. Induration
and thickening of the root of the sigmoid mesocolon is
not patl10gnomonic but highly suggestive of sigmoid
diverticulitis.
• On CT, associated diverticuli are seen in 84%, thickened
colonic wall in 79%, and pericolic fluid collections/
abscess in approximately 35% of cases.
• CT is not able to distinguish colon cancer from diverticulitis
in approximately 1 0% of cases.
• CT should be the primary method of radiologic diagnosis
as well as the method for evaluation and staging
of complicated diverticulitis.
• SUGGESTED READING
Birnbaum BA, Balthazar EJ . CT of appendicitis and diverticulitis.
Radiol Clin North Am 1994;32:885-898.
Johnson CD, Baker ME, Rice RP, et al. Diagnosis of acute colonic
diverticulitis: Comparison of barium enema and CT. AJR Am J
Roentgenol 1987; 148 : 54 1-546.
Neff CC, vanSonnenberg E. CT of diverticulitis: Diagnosis and
treatment. Radiol Clin North Am 1 989;27:743-752.
Pohlman T. Diverticulitis. Gastroenterol Clin North Am
1 988;1 7:357-358.

Front 69

A 55-year-old man has a 2-month history of anorexia, nausea and vomiting, and
guaiac-positive stool.

Back 69

Cancer: Primary malignancy, including the possibility
of synchronous tumors, must be considered in the
presence of malignant-appearing mass lesions and strictures.
• Crohn's disease: This disease is typified by multiple
skip and asymmetric lesions involving predominantly
distal small bowel and colon but may also involve
other segments of the gastrointestinal tract.
• Serosal implants from disseminated peritoneal disease:
The colon may be involved by disseminated
malignancy (e.g., ovarian cancer) , paraneoplastic
processes (e.g., endometriosis), and inflammatory conditions
(e.g., peritoneal abscesses) .
• Mesenteric metastases involving the colon: This is
the most likely diagnosis, with the gastric antral abnormality
representing the primary malignancy.
+ DIAGNOSIS: Mesenteric metastases to colon.
+ KEY FACTS
CLINICAL
• The colon is not uncommonly involved by metastases,
and indeed symptoms produced by such lesions may be
the initial manifestation of disseminated disease. The
colon may be involved by malignant spread via a number
of pathways, including direct invasion from an adjacent
tumor, spread via peritoneal ligaments and mesenteries,
and/or embolic hematogenous dissemination.
• Direct invasion of the colon commonly arises from the
prostate, ovary, uterus, cervix, kidney, and gallbladder.
The location of colonic involvement is determined by
the site of the adjacent primary tumor.
• Malignancy may reach the colon through the mesentery.
Carcinoma of the stomach will first involve the superior
border of the transverse colon by tracking down the
gastrocolic ligament. Pancreatic carcinoma may invade
the transverse colon via the transverse mesocolon and
will first involve the inferior border of the colon.
Carcinoma of the pancreatic tail may extend along the
phrenicocolic ligament to invade the splenic flexure.
143
• Intraperitoneal seeding most commonly occurs with
ovarian carcinoma but can also occur with gastric,
colon, and pancreatic malignancy. The locations of
these Ulmors are dictated by the flow of ascitic fluid
along peritoneal reflections. Tumor deposits will settle
in the most dependent portions of the peritoneal cavity,
which are the pouch of Douglas or rectovesicular
space. Other common sites are the medial border of
the cecum, superior border of the sigmoid colon, and
the right paracolic gutter.
• Hematogenous metastases most commonly arise from
melanoma but also from lung and breast carcinoma.
RADIOLOGIC
• Involvement of the colon by an adjacent tumor may
appear as simple extrinsic mass effect displacing the
colon witl10ut evidence of fixation or tethering, even if
actual serosal invasion has not yet occurred.
• Serosal involvement of the colon by tumor deposits,
whether by direct invasion, mesenteric spread, or
intraperitoneal seeding, will have a similar appearance .
The contour of the involved segment of bowel will
show puckering when viewed en face and spiculation
( "saw-tooth" contour) when viewed in profile. There
may be subtle mass effect. The segment of bowel will
be fixed and tethered.
• Serosal changes may also be created by endometriosis
and inflan1ffiatory processes such as peritoneal abscess.
• Hematogenous metastases manifest as a wide variety of
appearances, including bulky polyps, umbilicated or
ulcerated submucosal ("target" ) masses, armular or
eccentric strictures, or long infiltrative segments of
irregular narrowing.

Front 70

63-year-old woman with a palpable right upper quadrant mass

Back 70

Hypervascular metastases: Metastases to the liver
fr om an islet cell tumor of the pancreas, thyroid carcinoma,
breast carcinoma, and carcinoid tumors may be
hypervascular. Because hypervascular metastases may
enhance in a fa shion similar to normal liver parenchyma,
they may be difficult to detect during the portal
venous dominant phase of enhancement. However,
the peripheral globular enhancement in this case would
be atypical fo r any hypervascular metastases. Further,
willie metastases are typically of high signal intensity
compared to liver on T2 -weighted MRI, they are not
usually this "bright."
• Focal nodular hyperplasia: These tumors are hamartomas
and have imaging characteristics sinlliar to
hepatic parenchyma. On dynamic contrast-enhanced
CT during the hepatic arterial dominant phase, these
tumors typically have early intense uniform enhancement,
not present in this case. In about half of the
cases, there may be a central scar that may be of low
attenuation on a dynamic contrast- enhanced CT. On
T2-weighted MRI, these lesions may be slightly hyperintense
but often are quite subtle, with signal characteristics
sinlliar to those of normal liver.
• Hepatocellular carcinoma: These tumors are often
heterogenous "ugly" masses that may invade the portal
and/or hepatic veins. While they are often hypervascular,
they usually have areas of central enhancement due
to prominent central fe eding arteries; they lack the
peripheral globular enhancement shown in this lesion.
Patients with hepatocellular carcinoma often have
underlying cirrhosis, which is not present here.
• Metastatic colon cancer: Occasionally colon cancer
may present as a solitary mass in tlle liver. However,
colon carcinoma metastases are not hypervascular, very
rarely have delayed contrast enhancement, and are of
lower signal intensity on T2 -weighted MRI man
shown in this case.
• Cavernous hemangioma: This is me most likely diagnosis
given the peripheral nodular enhancement pattern
and centripetal "fill -in."
• DIAGNOSIS: Cavernous hemangioma of the liver.
KEY FACTS
CLINICA L
• Second to cysts, hemangiomas are tlle most common
benign tumor of the liver, with a reported incidence
ranging from 1% to 10%. There is a fe male predominance
of 4 to 1.
• Pathologically, the tumor represents numerous
endothelial-lined, blood-filled spaces. Larger heman-
145
giomas (::;20 cm) are nearly always heterogenous, with
central areas of fibrosis, necrosis, and cyst fo rmation .
Calcifications are uncommon.
• Hemangiomas are one of me fe w tumors that can be
confidently diagnosed using noninvasive imaging techniques,
including ultrasound, dynamic contrastenhanced
CT, MRI, or a Tc99m-tagged red blood cell
scintigraphy. Biopsy is rarely indicated unless the lesion
has atypical fe atures.
RADIOLOGIC
• On precontrast CT, hemangiomas are usually of unifo
rm low attenuation with well-circumscribed, lobulated
borders. On dynamic contrast-enhanced CT, hemangiomas
nearly always demonstrate globular enhancement
about the periphery. Over time (::;30 minutes) the
tumors "fill-in" in a centripetal fa shion. Large tumors
may have central areas of necrosis, fibrosis, or scar that
may not entirely "fill -in" with contrast material.
• On Tl-weighted MRI , the lesions are well circumscribed
and of low signal intensity compared to the
hepatic parenchyma. On a dynamic contrast-enhanced
MRI with a gadolinium-chelate, hemangiomas demonstrate
enhancement identical to that described fo r
dynamic CT. On T2-weighted MRI, hemangiomas typically
have a very high signal intensity, sinlliar to that of
a hepatic cyst or fluid in the gallbladder or spinal canal,
leading some to call hemangiomas "light bulb" lesions.
Because of this characteristic appearance, MRI has
proven useful in distinguishing hemangiomas fr om
other hepatic tumors.
• On ultrasound, hemangiomas are well circumscribed
and are uniformly hyperechoic relative to the liver
parenchyma. They may demonstrate enhanced
through-transmission but do not have a halo. Witll
color Doppler ultrasound, they usually do not have
central blood flow.
• On Tc 99 I1l-labeled red blood cell scintigraphy, hemangiomas
will appear as a defect in the early phases of the
scan that will "fill-in" on delayed scans. SPECT imaging
improves the accuracy in detecting and characterizing
small hemangiomas.
SUGGESTED READ

Front 71

A 30-year-old woman presents with right-upper quadrant pain and intermittent
jaundice.

Back 71

Loculated biloma: A biloma would be unlikely in the
absence of a history of recent trauma or biliary surgery,
and would not have a well-defined tubular appearance
on cholangiography.
• Enteric duplication cyst: These cysts can be of water
attenuation on CT but would be unlikely to follow the
Line of the cOl11mon bile duct and would not communlcate
with the biliary tree on cholangiography.
• Hepatic cyst: The extrahepatic location of this structure
on CT and communication with the biliary tree
on cholangiography excludes this diagnosis.
• Choledochal cyst: This is the most likely diagnosis
since on CT the cystic structure is in the expected
location of the extrahepatic biliary tree, and on cholangiography
the cyst is confirmed to be in continuity
with the biliary tree.
• Pancreatic pseudocyst: A pseudocyst could have this
appearance on CT, but the cholangiogram excludes
this diagnosis.
• Biliary cystadenoma: A cystadenoma would be
unlikely because of the extrahepatic location. Biliary
cyst adenomas are usually intrahepatic, of low attenuation,
and may have internal septa and a thick,
irregular wall.
• DIAGNOSIS: Choledochal cyst.
KEY FACTS
CLINICAL
• Choledochal cysts are an uncommon cause of biliary
obstruction and are characterized as cystic dilatation of
the extrahepatic or intrahepatic biliary tree, or both.
• They are three times more common in females than
males. Although they may present at any age, they are
typically discovered in children and young adults, with
60% presenting before the age of 1 0 years.
• The classic clinical triad of pain, jaundice, and abdominal
mass occurs in only 30% of patients.
• The etiology is unknown, but they are thought to be
related to an anomalous insertion of the common bile
duct (CBD) into the pancreatic duct proximal to the
ampulla, resulting in chronic reflux of pancreatic
147
enzymes into the biliary tree. They are associated with
other biliary anomalies, including a double CBD, double
gallbladder, absent gallbladder, atresia of bile ducts,
sclerosing cholangitis, congenital hepatic fibrosis, and
annular pancreas.
• Complications include cholangitis, biliary cirrhosis,
portal hypertension, calculi, and cyst rupture. They are
associated with an increased risk of carcinoma of the
bile duct.
RADIOLOGIC
• The diagnosis can be made with CT and ultrasound if
direct commwucation between the cyst and the biliary
tree can be shown . Appearances depend on the extent
of involvement and degree of dilatation . Scans may
show mild dilatation of the extrahepatic biliary tree, or
a large water attenuation mass in the porta hepatis.
• Cholangiography may be necessary to demonstrate
commwucation with the biliary tree. Percutaneous
transhepatic cholangiography ( PTq allows detailed
imaging of the intrahepatic ductal anatomy in addition
to imaging the cyst. Endoscopic retrograde cholangiopancreatography
( E RCP) provides detailed information
about the distal portion of the CBD and about
the often anomalous junction with the pancreatic duct.
• Tc99m-hepatobiliary scanning shows late filling of the
cyst with delayed clearance, and effectively excludes all
other possibilities from the differential diagnosis.
• Type I: the most common type ( 89% to 90%), characterized
by cystic or fusiform dilatation of the CBD
• Type I I (2%): diverticulum from the CBD
• Type III ( 1 % to 5%): choledochocele; characterized by
dilatation of the intraduodenal portion of the CBD
• Type IV: multiple cysts of the extrahepatic and intrahepatic
bile ducts
• Type V: Caroli's disease; multiple intrahepatic duct cysts

Front 72

A 54-year-old white woman has had right-upper quadrant pain over a period of 1
week. Jaundice developed within the previous 48 hours. On examination she was
febrile, and initial blood work revealed leukocytosis.

Back 72

DIFFERENTIAL DIAGNOSIS
• Gallbladder carcinoma: A malignant mass arising from
the gallbladder neck and extending to the common
hepatic duct may produce this cholangiographic appearance.
Conversely, an aggressive cholangiocarcinoma
extending to the cystic ducts needs to be considered.
• Lymphadenopathy: The strategic position of the
common hepatic duct in the porta hepatis allows it to
be compressed by lymphadenopathy and other mass
lesions in this location.
• Mirizzi's syndrome: This is the most likely diagnosis
given this constellation of clinical findings (acute
cholecystitis with obstruction) and imaging findings
( extrinsic-appearing obstruction of the common hepatic
duct and impaired opacification of the gallbladder
suggestive of partial cystic ductal obstruction).
+ DIAGNOSIS: Mirizzi's syndrome.
+ KEY FACTS
CLINICAL
• In Mirizzi's syndrome, there is jaundice because of
obstruction of the common hepatic duct at its junction
with the cystic duct, which is due to periductal inflammatory
changes occurring around a calculus impacted
in the distal cystic duct.
• Patients present with features of acute cholecystitis
( abdominal pain and tenderness, fever, and leukocytosis)
as well as jaundice. Occasionally, jaundice resolves
spontaneously with conservative management of the
cholecystitis.
149
• It is important to make this diagnosis before operative
management because it is difficult to identifY the various
ducts coming out of the resultant inflammatory mass. As a result, the surgeon may inadvertently ligate the
common hepatic duct, mistaking it for the cystic duct.
• Type I Mirizzi's syndrome occurs when there is an
impacted calculus in the cystic duct. Type I I is much
less common and occurs when a stone erodes from the
gallbladder into the bile duct.
RADIOLOGIC
• Plain radiographs may demonstrate the offending calculus
if sufficiently radiodense, especially if one of the
stones is seen to be separate and more medial to the
main cluster of gallstones. The plain film is also useful
for correlation with cholangiographic or CT studies.
• Cholangiography typically demonstrates a smooth, lateral,
extrinsic narrowing of the common hepatic duct.
There will be proximal biliary dilatation, and a calculus
may actually be visible in the adjacent, expected position
of the cystic duct.
• On CT scan, an inflammatory mass will be seen in the
porta hepatis. The greater contrast resolution of CT
usually allows visualization of the cystic duct calculus.
The nonspecific features of acute cholecystitis and biliary
dilatation may also be present.

Front 73

A 65-year-old man with jaundice and anorexia

Back 73

Cholangiocarcinoma: Hilar type (Klatskin tumor).
This is the most likely diagnosis to explain all the signs
observed .
• Sclerosing cholangitis: This can result in tight biliary
strictures that will extend over a long segment. However,
the absence of ectasia or stricturing elsewhere in the biliary
tree makes this diagnosis less likely.
• Hepatic or hilar tumor: Bile ducts may be compressed
by adjacent primary hepatic or metastatic hilar
or hepatic tumor deposits. The absence of visible mass
lesions on CT scan would not support this possibility.
• Trawnatic biliary stricture: A relevant history of biliary
trauma, including violent injury, iatrogenic (surgical)
misadventure, or a deliberate biliary diversion procedure
would be required to consider this possibility.
+ DIAGNOSIS: Hilar cholangiocarcinoma
(Klatskin tumor ).
+ KEY FA CTS
CLINICAL
• Clinical presentations include jaundice, anorexia,
weight loss, vague abdominal discomfort, and abnormal
Liver function tests.
• Ri sk fa ctors include sclerosing cholangitis, choledochal
cysts, congenital hepatic fibrosis, Clonorchis sinensis
infection, and thorotrast exposure .
• Most cholangiocarcinomas are fo und at the hepatic
duct confluence, as in this case. Distal duct and intrahepatic
types are less commonly seen.
• Morphologically, the hilar type is usually a scirrhous
infiltrating tumor causing a stricture. The intrahepatic
type appears as a nonspecific, ill-defined mass lesion
with contrast enhancement and areas of necrosis . The
distal duct type is usually small and appears as a short
stricture or a small polypoid mass.
151
RADIOLOGIC
• Cholangiocarcinoma of the hilar type is usually scirrhous
in nature . The resulting tumor is infiltrative and
usually poorly defined. There is associated marked biliary
dilatation above the obstruction and hepatic atrophy
of the segments involved .
• Ultrasonography is most useful to identify dilated
ducts, as well as segmental or lobar atrophy seen as
crowded dilated bowel ducts . The tumor mass is normally
not seen, but if it is, it usually appears echo genic .
• CT is most sensitive in detecting the offending mass,
which will appear less dense than the normal liver on
precontrast scans. Following intravenous contrast material
administration, a variable enhancement pattern is
seen, and some tumors demonstrate delay enhancement
several minutes after the injection. CT is very sensitive
to the detection of associated lobar atrophy.
• Imaging is used to assess extension of tumor, most
commonly to the liver parenchyma and the hepatoduodenal
ligame nt. Lymphadenopathy may be recognized
but is often underestimated due to the presence
of tumor extension to normal-sized nodes . Va scular
invasion is relatively unusual .
• Cholangiography is required to evaluate the extent of the
tumor. The severity of the obstruction often requires
opacification of ducts both from above and below, and
requires correlation with cross-sectional imaging to
ensure that all obstructed segments are opacified

Front 74

A 67-year-old woman presents with abdominal pain and weight loss.

Back 74

DIFFERENTIAL DIAGNOSIS
• Pancreatic carcinoma: This diagnosis is unlikely in
view of the calcifications, which are rarely seen in
pancreatic adenocarcinoma.
• Cystic pancreatic neoplasm: A microcystic adenoma
of the pancreas may contain calcification, but small
cysts, typically <2 cm in diameter, would also be visible.
• Pancreatic islet cell tumor: These tumors may calcifY
but typically show marked enhancement due to
hypervascularity.
• Chronic pancreatitis: Pancreatitis often manifests as
diffuse glandular enlargement, although it may present
as a focal mass. Parenchymal and/or intraductal calcifications
may or may not be present.
+ DIAGNOSIS: Chronic pancreatitis.
+ KEY FACTS
CLINICAL
• Symptoms at presentation are usually nonspecific,
although patients may have either or both weight loss
and upper abdominal pain.
• A history of long-term alcohol abuse is often present.
• Most patients have had a prior episode of acute pancreatitis;
with each episode, there is progressive pancreatic
parenchymal destruction.
153
RADIOLOGIC
• Endoscopic retrograde cholangiopancreatography
( E RCP) is the most sensitive test for early disease, as
duct strictures, side branch enlargement, and intraluminal
filling defects may be seen before CT and ultrasound
changes occur.
• Intraluminal filling defects in the pancreatic ducts on
ERCP usually represent mucin collections, which may
be detected before they calcifY and thus before they
are apparent on CT.
• Either CT or ultrasound may show a heterogenous
gland due to the presence of fat and fibrosis. Encapsulated
fluid collections or pseudocysts may also be present.
• The gland size is variable and may be involved either diffusely
or focally. The gland may be normal in size, small
(atrophy of the gland), or large (recent pancreatitis).
• CT may also show a focal mass with or without dilatation
of the pancreatic and/or bile ducts.
• Calcifications are present in only 50% of cases, therefore a
noncalcified mass can still represent chronic pancreatitis.
+ SUGGESTED READING
Ferrucci JT, Wittenberg J, Mack EB, et a!. Computed body tomography
in chronic pancreatitis. Radiology 1979; 1 30: 1 75-1 82 .
Luetmer P H , Stephens DH, Ward E M . Chronic pancreatitis:
Reassessment with current CT. Radiology 1989; 1 71 : 3 5 3-357.

Front 75

A 27-year-old woman has upper abdominal discomfort. She had been well previously.

Back 75

DIFFERENTIAL DIAGNOSIS
• Pancreatic pseudocyst: The pancreatic body and tail
are good locations for pseudocysts, but the patient
would be expected to have a previous history of pancreatitis.
Pseudocysts often communicate with the pancreatic
duct at ERCP.
• Mucinous cystic tumor: This is the most likely diagnosis
since these tumors typically have one or a few
large cysts ( >2 cm) and well-defined septations.
Calcifications are uncommon.
• Serous cystic tumor: This diagnosis is unlikely as the
classical features of numerous small cysts « 2 c m) with
an enhancing central "scar" are not present. These
tumors often show calcifications.
+ DIAGNOSIS: Mucinous cystic tumor.
+ KEY FACTS
CLINICAL
• Cystic pancreatic tumors are much less common than
pancreatic ductal adenocarcinoma.
• They typically occur in 40- to 60-year-old patients;
women are more common than men (9 to 1 ).
• Symptoms such as pain or jaundice are uncommon.
The cysts are often an incidental finding.
155
• Although these tumors have malignant potential, they
are slow growing and have an indolent course .
RADIOLOGIC
• CT or ultrasound shows a cystic mass, typically <6
cysts in number and >2 cm in size, with thin or thick
intervening septa.
• Calcifications are seen in 1 4%. There is no central scar.
(A central scar is typical of a serous tumor. )
• Communication with the pancreatic duct is uncommon
at E RCP, unlike pseudocysts.
• Radiologically, one cannot differentiate a cystadenoma
from a cystadenocarcinoma.
• A biopsy is indicated if there is no good history of pancreatitis
to exclude pseudocyst and also to differentiate
benign from malignant tumors. Histologically, the mucinous
tumors almost always have some foci of malignancy.
• SUGGESTED READING
Friedman AC, Lichtenstein JE, Dachman AH. Cystic neoplasms of
the pancreas: Radiological-pathological correlation. Radiology
1983; 149:45-50.
Itai Y, Moss AA, Ohtomo K. Computed tomography of cystadenoma
and cystadenocarcinoma of the pancreas. Radiology
1982;145:4 1 9-425 .

Front 76

A 6 1 -year-old woman has weight loss and a history of peptic ulcer disease.

Back 76

DIFFERENTIAL DIAGNOSIS
• Pancreatic islet cell tumor, nonfunctioning: These
tumors do not secrete hormones and are clinically
silent. Hence, they are often of larger size at presentation
than functioning tumors. They may calcify.
• Pancreatic islet cell tumor, functioning: Gastrinoma
is a likely diagnosis in view of the history of peptic
ulcer disease . Insulinomas are the most common
functioning tumor but are usually small and not associated
with peptic ulcers. Calcifications are rare in
functioning tumors.
• Pancreatic hypervascular metastasis (e.g., renal):
This diagnosis is unlikely since pancreatic metastases
are usually not isolated.
+ DIAGNOSIS: Gastrinoma.
+ KEY FACTS
CLINICAL
• These tumors present early with symptoms of gastric
hypersecretion ( Zollinger-Ellison syndrome [ ZES ] ) .
• Peptic ulcers are often resistant to medical management
and present in atypical locations-e .g., the postbulbar
region. The most common location continues
to be the duodenal bulb.
157
• They are associated with multiple endocrine neoplasm
syndrome, type 1 .
RADIOLOGIC
• Islet cell tumors are very vascular and, when large
enough, are seen on CT as an enhancing pancreatic
mass.
• Up to 50% of gastrinomas have metastasized to the
liver at the time of presentation ( typically hyperenhancing
metastases); hence, CT is important for staging.
By comparison, only 1 0% of insulinomas will have
metastases at the time of presentation.
• Barium studies often show associated peptic ulcers,
which may be multiple and/or postbulbar.
• Gastrinomas causing ZES usually originate in the head
of the pancreas or the duodenum.
+ SUGGESTED READING
Frucht H, Doppman JL, Norton JA, et al. Gastrinomas: Comparison
of MR imaging with CT, angiography and ultrasound. Radiology
1989; 1 7 1 :7 1 3-7 1 7.
Semelka RC, Ascher SM. MR Imaging of the pancreas. Radiology
1 99 3 ; 1 8 8 : 593-602.
Wank SA, Doppman JL, Miller DL, et al. Prospective study of the
ability of computed axial tomography to localize gastrinomas in
patients with Zollinger-Ellison syndrome. Gastroenterology
1987;92:905-9 1 2

Front 77

A 5 5-year-old woman presents with progressive back pain and rapid weight loss.

Back 77

DIFFERENTIAL DIAGNOSIS
• Pancreatic adenocarcinoma: This patient has the classic
appearance of a pancreatic carcinoma: a nonenhancing
mass in the pancreatic head associated with
obstruction of the pancreatic duct and atrophy of the
body and tail.
• Chronic pancreatitis: There may be a focal mass in
patients with chronic pancreatitis that, in the absence
of calcifications ( 50%), is indistinguishable from pancreatic
carcinoma. It often requires a biopsy to make
this distinction.
• Pancreatic lymphoma: Lymphoma rarely arises in the
pancreas. Involvement of peripancreatic nodes is more
typical. Associated abdominal lymphadenopathy would
also be expected.
• Pancreatic metastases: Malignancy of the lung, breast,
kidneys, or gastrointestinal tract may spread hematogenously
to the pancreas. This diagnosis should be considered
if there is a history of a primary malignancy.
+ DIAGNOSIS: Pancreatic adenocarcinoma.
+ KEY FACTS
CLINICAL
• Pancreatic carcinoma presents late in the course of the
disease, usually with liver and nodal metastases. Less
than 30% are resectable at initial presentation.
159
• Pancreatic carcinoma is more common in males and
blacks.
• There is an association between pancreatic carcinoma
and smoking and familial pancreatitis. There is no
association, however, with alcohol use .
RADIOLOGIC
• Typically, a focal mass is present ( 75% in the pancreatic
head) . On contrast-enhanced CT, 95% are of low
attenuation . Typically the masses are nonenhancing,
but they may appear isoattenuating postcontrast.
• The pancreatic duct may be dilated and the pancreatic
parenchyma atrophic.
• Local extension is present in 90% of patients-i.e., either
or both into the duodenum and the celiac/porta hepatis
lymph nodes. Vascular encasement (superior mesenteric
or celiac artery) indicates an unresectable tumor.
• CT is 95% accurate in determining unresectability, but
it is only 50% accurate in determining resectability as
small liver metastases and peritoneal implants may not
be detected.
+ SUGGESTED READING
DelMaschio A, Vanzulli A, Sironi S, et al. Pancreatic cancer versus
chronic pancreatitis: Diagnosis with CA 19-9 assessment US
CT, and CT-guided fine-needle biopsy. Radiology
"
1 99 1 ; 1 78 :95-99.
Zeiss J, Coombs RJ, Bielke D. CT presentation and staging accuracy
of pancreatic adenocarcinoma. J Pancreatol 1990;7:49-5 3 .

Front 78

A 30-year-old man with a history of intravenous drug abuse presents with fever
and abdominal pain.

Back 78

Pyogenic abscess: In the immunocompetent patient,
an abscess is usually due to aerobic organisms, including
Salmonella, which develop in the setting of underlying
splenic damage .
• Opportunistic infection: In the immunocompromised
patient, unusual organisms including fungi,
Mycobacterium tuberculosis, M. avium-intracellulare,
and Pneumocystis carinii may infect the liver and
spleen. The lesions usually appear as multiple microabscesses.
• Lymphoma: Diffuse histiocytic or immunoblastic
types of lymphoma are seen occasionally as ill-defined,
low-attenuation splenic masses on CT.
• Hematoma: This should be considered in the context
of trauma or a coagulopathy, either due to an underlying
disease state or as a result of therapy.
• Metastases: Apart from malignant melanoma, macroscopic
metastases to the spleen are very unusual. In the
immunocompromised patient, disseminated Kaposi's
sarcoma may occur, although there is usually evidence
of disseminated disease elsewhere.
• Cysts: Simple cysts are relatively uncommon and
appear as round, well-defined, water attenuation lesions
but become atypical in appearance if complicated by
infection or hemorrhage. Hydatid cysts ( Echinococcus
infection) should be considered in patients exposed to
areas where this condition is endemic.
+ DIAGNOSIS: Splenic abscesses, Candida.
+ KEY FACTS
CLINICAL
• Splenic abscesses are uncommon, but their frequency
has grown because of an increasing number of
immunocompromised patients. Specific diseases at risk
for splenic abscess include sickle cell anemia, childhood
granulomatous disease, and diabetes mellitus.
• The spleen may be infected by several routes, including
metastatic hematogenous infection ( e .g., bacterial
endocarditis), contiguous infection (e.g., infected pancreatitis),
infection of splenic infarcts, trauma, and
immunodeficiency states. One-fifth of splenic abscesses
have no apparent underlying source.
• The mortality rate for splenic abscess has historically
been very high-up to 70%-but with earlier diagnosis
by imaging, improved antibiotic therapy, image-guided
diagnostic aspiration for identification of organisms, as
well as for percutaneous drainage, the mortality has
been reduced to < 1 0%.
• Over half of splenic abscesses are infected by aerobic
organisms, especially gram-positive cocci. Fungi are
found in about one-fourth of splenic abscesses.
161
• The classic clinical picture of a splenic abscess is comprised
of fever, chills, left-upper quadrant pain and tenderness,
and splenomegaly. However, the majority of
patients do not present with this classic picture early in
the disease process, and signs localizing to the left
upper quadrant are often absent.
• Complications of an abscess, such as rupture, subphrenic
abscess, and peritonitis, will occur if the diagnosis
is delayed, and these are associated with a high
mortality rate.
RADIOLOGIC
• CT is the optimum diagnostic modality for the diagnosis
of splenic infection, with a reported sensitivity of
up to 96%. Not only will this technique localize a
splenic abscess but it will also provide anatomic and
diagnostic information about the perisplenic area, is
useful for showing evidence of adjacent disease, and
helps plan for surgical or radiologic intervention.
• A bacterial abscess appears as a low-attenuation mass
lesion with an ill-defined, thick, and irregular rim.
There may be slight peripheral enhancement.
Occasionally, the abscess contains gas. There may be
internal septa and/or fluid-debris levels.
• Fungal infections essentially occur only in immunocompromised
patients. The lesions are usually small, typically
<2 cm in diameter and usually <5 mm. These lesions
are therefore difficult to detect on imaging. When seen,
they appear as nonenhancing, low-attenuation lesions
on CT. Occasionally, they may demonstrate a "bull's
eye" appearance on ultrasound or CT. Tuberculosis
commonly involves the spleen in its miliary form.
However, the lesions are usually small, <1 cm in size,
and difficult to visualize on imaging. The macronodular
form of the disease (tuberculoma) is a rare manifestation'
appearing as large, single or multiple, ill-defined
low-attenuation masses.
• In the patient with AIDS, the spleen may be infected
by M. avium-intracellulare or P carinii organisms.
The individual infected foci are usually tiny, resulting
only in splenomegaly on imaging. Over time, the
lesions may calcifY.
• Image-guided intervention is an ideal method of sampling
these lesions to allow for identification of the
organism(s ) . Percutaneous abscess drainage is a reasonable
option to surgical resection, and on occasion is
completely curative.

Front 79

A 48-year-old man with fever and generalized abdominal pain.

Back 79

Hepatic metastasis: Metastases can diminish in size or
disappear after chemotherapy, although the shape of
the mass favors a lesion in the portal vein. Furthermore,
malignant portal vein thrombosis is more commonly
associated with hepatocellular carcinoma than
with metastases.
• Hepatocellular carcinoma (HCC): RCC is often
associated with either portal vein or hepatic vein
thrombosis. The thrombus may be bland or malignant.
Furthermore, malignant thrombosis can even occur
with a tumor that is remote from a major vein. This
diagnosis, however, is unlikely since the mass diminished
on the 6-week follow-up examination.
• Traumatic laceration of the liver: Lacerations can
have an unusual, somewhat angular shape, although
they usually extend to the capsular surface of the liver
and are associated with perihepatic or subcapsular
hemorrhage.
• Portal vein thrombosis (PVT) with cavernous
transformation: This is the most likely diagnosis since
there is a mass in the lumen of the portal vein that is
replaced by a nest of collateral veins within a relatively
short period of time (several weeks) .
• Hepatic infarction: Infarcts present a s wedge-shaped,
hypoattenuating parenchymal defects that originate
from the central portion of the liver and extend to the
capsular surface . In time, bubbles may develop, and
later they become more rounded and cystic in nature .
DIAGNOSIS: Portal vein thrombosis with
cavernous transformation.
KEY FACTS
CLINICAL
• Pediatrics: Idiopathic PVT is the principal cause of
portal hypertension. Patients present with variceal
hemorrhage without elevation of liver enzymes. They
often have splenomegaly, but ascites is uncommon.
Other causes include neonatal septicemia, omphalitis,
or umbilical vein catheterization.
• Adults: Causes of PVT include cirrhosis (due to either
or both slow flow and intimal hyperplasia), inflammatory
and neoplastic pancreatic diseases, inflammatory
processes involving the gastrointestinal tract (pyothrombophlebitis
is rare), pregnancy, and oral contraceptives.
163
• PVT is characterized as being extrahepatic and/or intrahepatic.
In extrahepatic PVT, peribiliary venous collaterals
enlarge and reconstitute the intrahepatic portal
branches if patent (cavernous transformation).
RADIOLOGIC
• Portal venous thrombi that partially occlude the lumen
may propagate proximally and/or distally, progress to
complete occlusion, or diminish/resolve following
anticoagulant therapy.
• Portal venous thrombi that totally occlude the lumen
tend to be replaced by a nest of small collaterals, and
this process occurs over a several-week period. The
thrombus itself tends to shrink in size and is often difficult
to identify. Occasionally the thrombus calcifies.
Cavernous transformation is best demonstrated by a
contrast-enhanced CT or an MRI with either a whiteblood
or black-blood technique. Although ultrasound
is helpful at times, particularly using color Doppler, it
tends to lUlderestimate collateral formation.
• PVT can be either bland or malignant in the presence
of hepatic malignancy, especially hepatocellular carcinoma.
Thrombosis can develop even if the tumor is
remote to the portal vein. Malignant thrombosis is
suspected when enhancement is demonstrated postcontrast
material, particularly when it occurs in the
hepatic arterial dominant phase. The presence of arterial
signal within the thrombus on Doppler ultrasound
is also diagnostic. At times, a percutaneous biopsy is
required to make tllis differentiation.
• PVT often develops in patients with an inflammatory
process along the venous system draining the abdominal
viscera. Therefore, it is prudent to look also for tlle
presence of enteritis, inflammatory bowel disease,
diverticulitis, appendicitis, or an abscess.

Front 80

A 42-year-old woman presents with vague abdominal pain.

Back 80

Hepatocellular carcinoma (HCC): Some welldifferentiated
hepatomas may have these attenuation
and enhancement characteristics, but when as large as
this particular lesion, they are usually heterogenous.
• Hepatocellular adenoma: In the absence of internal
hemorrhage, these benign tumors may have an identical
appearance. A history of oral contraceptive use
might suggest favoring adenoma over focal nodular
hyperplasia.
• Hypervascular metastasis: Many of these metastatic
implants will be visualized only in the hepatic arterial
phase, although when they are this large, they are usually
hypoattenuating precontrast as well as hypoattenuating
in the portal venous dominant phase.
• Cavernous hemangioma: This mass has no enhancement
features of a hemangioma. The peripheral nodular
or cotton-wool enhancement pattern characteristic
for these benign lesions is not present.
• Focal nodular hyperplasia (FNH): This is the most
likely diagnosis since the mass has the classic features
of FNH, particularly when the lesions are this large. A
hepatic adenoma without internal hemorrhage, however,
could have a similar appearance.
• Regenerating nodule: These masses are predominantly
supplied by the portal vein, similar to normal
parenchyma, and do not enhance significantly in the
hepatic arterial dominant phase.
+ DIAGNOSIS: Focal nodular hyperplasia.
+ KEY FACTS
CLINICAL
• FHN is much more common in woman ( 85%); they
typically present in the third to fifth decade of life.
• They are usually asymptomatic and therefore detected
incidentally. Only 1 0% are symptomatic, presenting
with an abdominal mass or pain.
• FNH are not associated with oral contraceptives,
although there is evidence that oral contraceptives
165
increase the otherwise low propensity for intra tumoral
hemorrhage.
• The alpha-fetoprotein level is normal.
• FNH are benign tumors that do not degenerate into
well-differentiated hepatocellular carcinomas.
RADIOLOGIC
• Histologically, FNH are composed of hepatocytes, bile
ducts, and Kuppfer cells to a variable degree (there is a
much higher population of Kuppfer cells compared to
adenomas), laid along fibrous strands that coalesce
centrally to form a scar. These features determine the
imaging fmdings.
• Most FNH are solitary, but 20% are multiple.
• Classically, they are isoattenuating precontrast, hyperattenuating
during the hepatic arterial dominant phase,
and isoattenuating during the portal venous dominant
phase. These differences are reflected in Tc99m-sulfur
colloid scintigraphy.
• A central hypoattenuating scar is present about 50% of
the time, but this finding is not specific for FNH as it
can also be seen in hepatic adenomas and hepatocellular
carcinomas. On MR!, the scar tends to be of high
signal intensity on T2-weighted images in FNH and of
low signal intensity in HCC.

Front 81

A 62-year-old man has a long-standing history of postprandial abdominal bloating.
Laboratory values include a normal bilirubin level and slight elevation of alkaline
phosphatase, serum glutamic-oxaloacetic transaminase, and serum glutamic-pyruvic
transaminase.

Back 81

Bile duct carcinoma: Bile duct carcinomas typically
have the appearance of a short biliary stricture and
proximal biliary obstruction. In the case illustrated
here, the intrahepatic biliary system is diffusely
involved . Bile duct carcinoma can rarely involve much
of the biliary system in a diffuse fashion. It should be
remembered that bile duct carcinoma can occur secondary
to underlying primary sclerosing cholangitis,
another cause of biliary duct narrowing.
• Primary sclerosing cholangitis (PSC): The appearance
of multifocal strictures diffusely involving the biliary tree
is typical of PSc. This is the most likely diagnosis.
• Secondary sclerosing cholangitis: This process has a
radiologic appearance that simulates that of PSC. The
clinical history is important in distinguishing the two
entities. Secondary sclerosing cholangitis is associated
with a history of recurrent biliary infections from calculus
disease, a surgical stricture, or a choledochoenterostomy,
all features that are absent in the case presented .
+ DIAGNOSIS: Primary sclerosing cholangitis.
+ KEY FACTS
CLINICAL
• PSC is a rare, chronic hepatobiliary disease of
unknown cause. It is characterized by patchy, progressive
fibrosis of either the intrahepatic or extrahepatic
biliary ducts, or both.
• PSC is seen primarily in males, with a male-to-female
ratio of 3 to 1 . It typically occurs in the third to fifth
decades.
• PSC is associated with inflammatory bowel disease.
Sixty percent of patients have ulcerative colitis. On the
other hand, between 1% and 4% of patients with
chronic ulcerative colitis develop PSC . Five percent of
patients with PSC have Crohn's disease.
• The HLA-B8 antigen is present in 60% to 80% of
patients with PSc.
167
• PSC seems to originate in the intrahepatic ducts and
progresses to involve the extrahepatic ducts. Extrahepatic
ductal involvement eventually occurs in >90%
of patients. Some studies indicate that intrahepatic
ducts are almost always included (often to a greater
degree than extrahepatic ducts ) .
• No histologic feature i s pathognomonic for PSc.
Typically, concentric layers of connective tissue surround
the ducts, with a sparse, mixed inflammatory
infiltrate .
• PSC can progress to biliary cirrhosis or bile duct
carcinoma.
• The diagnosis is based on clinical features ( recurrent
right-upper quadrant pain and symptoms of chronic
cholestasis, including jaundice and pruritus) and the
appearance at cholangiography. The clinical and histologic
frndings overlap with those of primary biliary
cirrhosis. However, the latter entity typically affects
middle-aged women, does not involve the extrahepatic
ducts, and is associated with high titers of antimitochondrial
antibodies.
RADIOLOGIC
• The appearance of PSC at cholangiography is that of
multifocal strictures that are diffusely distributed, usually
involving both the intrahepatic and extrahepatic
bile ducts.
• On occasion, the disease is confined to the intrahepatic
or extrahepatic ducts alone.
• The strictures are usually short and annular, and located
between normal or slightly dilated segments.

Front 82

Patient A: a 3 1 -year-old woman who had been in a motor vehicle accident presents
with gross hematuria. Patient B: a 2 1 -year-old woman who also had been in a
motor vehicle accident presents with microscopic hematuria.

Back 82

The differential diagnosis for both patients includes
intraperitoneal bladder rupture, extraperitoneal
bladder rupture, or a combination of the two.
• In patient A, intraperitoneal rupture is diagnosed
because the contrast outlines the right paracolic gutter
and liver.
• In patient B , extraperitoneal rupture is diagnosed
because the contrast material does not flow into the
peritoneal cavity but extends into the proximal tlligh
via the left inguinal region. There is an associated fracture
of the inferior pubic ramus.
+ DIAGNOSIS: Patient A: intraperitoneal bladder
rupture. Patient B: extraperitoneal bladder rupture.
+ KEY FACTS
CLINICAL
• Bladder rupture can be seen following blwlt or penetrating
trauma and may be extraperitoneal, intraperitoneal,
or both.
• Extraperitoneal bladder rupture is more common,
composing approximately 80% of cases, and is frequently
associated with pelvic fractures. The rupture
usually occurs at the base of the bladder. I ntraperitoneal
bladder rupture occurs at the dome of the bladder
when the bladder is distended. Pelvic fractures are
seen less commonly in intraperitoneal bladder rupture
than in extraperitoneal bladder rupture.
• I ntraperitoneal rupture is more common in children
than adults.
• Physical findings of bladder rupture include hematuria
and the inability to urinate. Significant hematuria ( > 5 0
red blood cells/high-power field) i s a sensitive indicator
of bladder trauma.
171
• Intraperitoneal bladder rupture requires surgery with
bladder closure, whereas extra peritoneal bladder rupture
can be managed with catheter drainage, antibiotics, and
clinical follow-up.
RADIOLOGIC
• Radiologic diagnosis includes conventional cystography
and CT of the abdomen and pelvis, including CT
cystography.
• I n extraperitoneal rupture, there are often associated
fractures of tlle pubic rami or anterior pelvic ring. The
extravasated contrast material can track down into the
proximal thigh or scrotum. The extravasated contrast
material may be ill-defined and feathery or contained.
• Wiili intraperitoneal rupture, ilie contrast material
flows freely into the peritoneum and may outline
bowel loops or the paracolic gutters.
• CT of the abdomen and pelvis performed witll the
bladder only mildly or moderately distended is not as
sensitive as conventional cystography for bladder injury.
However, recent articles have demonstrated that CT
cystography is comparably sensitive to conventional cystography.
The bladder must be well distended on the
CT study, either from instillation of contrast material
wough a Foley catheter or by using delayed images.
Postdrainage CT images should also be obtained.
+ SUGGESTED READING
Bodner DR, Selzman AA, Spirnak J P. Evaluation and treatment of
bladder rupture. Semin Urol 1995; 1 3 :62-65.
Horstman WG, McClennan BL, Heiken JP. Comparison of computed
tomography and conventional cystography for detection of
traumatic bladder rupture. Urol Radiol 1 99 1 ; 1 2 : 1 8 8-193.
Rehm CG, Mure AI, O'Malley KF, Ross SE. Blunt traumatic bladder
rupture: The role of retrograde cystogram. Ann Emerg Med
1 99 1 ;2 0 :845-847.

Front 83

A 56-year-old woman presents with a low-grade fever.

Back 83

Renal tuberculosis (TB): This is the best diagnosis due
to extensive replacement of the nonfunctioning right
kidney by calcification, producing a "putty" kidney.
Calcifications in the ureter are also typical. Pyonephrosis
is present in the lower pole of the left kidney.
• Granulomatosis pyelonephritis: This inflammatory
process is usually related to a staghorn calculus.
Calcification in the ureter is atypical.
• Schistosomiasis: This infection characteristically affects
the distal ureters, causing dilation and/or stenosis. The
proximal ureters and ureteropelvic junctions are rarely
involved. Schistosomiasis typically causes bladder calcification,
but renal calcifications are uncommon.
+ DIAGNOSIS: Tuberculosis with right autonephrectomy
and left lower pole pyonephrosis.
+ KEY FACTS
CLINICAL
• Renal TB results from hematogenous spread of tuberculous
bacilli to the kidneys. Ureteral involvement is
secondary to bacilluria from the kidneys.
• Although both kidneys are usually involved, the disease
process is typically more severe in one kidney.
• Patients are typically >40 years and present with hematuria,
frequency, dysuria, or suprapubic pain.
• Ten percent of patients may be asymptomatic and have
sterile urine .
RADIOLOGIC
• Radiographic findings depend on the extent of the disease
process but are present in the majority of cases of
renal TB .
• Papillary necrosis is common and may be extensive.
Necrosis in renal granulomas may lead to the formation
of communicating cavities.
173
• Parenchymal calcifications are present in 50% of
patients. They may be amorphous in association with
granulomatous masses, or dense in healed tuberculomas.
Renal calculi develop in 20% of patients.
• Parenchymal scarring occurs in 20% of patients, either
localized or involving the entire kidney. There are also
associated calcifications and underlying calyceal abnormalities.
• Calyceal abnormalities are common, with multiple
irregular strictures of the infundibula and subsequent
hydrocalycosis.
• Renal function is impaired in 50% of patients. Antegrade
or retrograde pyelography is required for
evaluation.
• Advanced disease eventually results in a nonfunctioning
kidney ( autonephrectomy or "putty" kidney) .
These cases are associated with extensive calcifications.
• Failure of contrast material excretion often signifies the
presence of tuberculous pyonephrosis due to stricture
formation.
• Abnormalities of the ureters occur in 50% of cases of
renal TB due to ulceration, with fibrosis, stricture, and
calcification. Alternating segments of dilation and
stricture produce a characteristic beaded appearance.
Shortening of the ureter may also occur, producing a
"pipestem" appearance.
• Other sites of urinary tract involvement include the
prostate, epididymis, scrotum, and bladder, producing
calcification with abscess formation and fistulous tracts.
+ SUGGESTED READING
Renal Inflammatory Disease. In NR Dunnick, RW McCallum, CM
Sandler (eds), Textbook of Uroradiology. Baltimore: Williams &
Wilkins, 1 99 1 ; 1 35- 1 5 7 .
The Ureter. In NR Dunnick, RW McCallum, CM Sandler (eds),
Textbook of Uroradiology. Baltimore: Williams & Wilkins,
1991 ;287-3 1 9 .
Elkin M.UrogenitaJ Tuberculosis. In HM Pollock, H Elkin (cds),
Clinical Urography. Philadelphia: Saunders, 1990;1020-1052.

Front 84

A 70-year-old man has a prior history of urinary tract surgery.

Back 84

DIFFERENTIAL DIAGNOSIS
• Recurrent transitional cell tumor: The urinary diversion
procedure suggests surgery for previous carcinoma
of the bladder. The mass and filling defects within
the right ureter may represent either a recurrent or a
metachronous transitional cell carcinoma (TCC).
• Obstructing blood clot: A blood clot could form in
the right ureter, particularly since there has been
recent surgery. This diagnosis would also be favored if
there were a history of anticoagulation therapy.
• Infectious debris (fungus ball): A collection of thick
debris, especially in the presence of infection, could
cause obstruction of the ureteropelvic junction or the
right ureter.
+ DIAGNOSIS: Recurrent and obstructing transitional
cell carcinoma of the right mid-ureter.
+ KEY FACTS
CLINICAL
• Pain and hematuria are the most common presenting
features of recurrent TCC.
• In a patient with a previous history of bladder carcinoma,
pain and hematuria may represent recurrent tumor
either within the residual bladder or in the upper tracts.
175
RADIOLOGIC
• Forty percent of patients present with a nonfunctioning
kidney on intravenous urography due to longstanding
ureteral obstruction.
• A filling defect in the lumen of the ureter is the key
diagnostic finding.
• Multiple polypoid discrete masses within the pelvicalyceal
system or ureter are a common finding.
• "Bergman's sign" is dilation of the ureter distal to a
ureteral mass not associated with a renal calculus.
• Localized expansion of the ureter at the level of the
tumor ( "champagne glass" or "wine goblet" deformity)
is a key fmding.
• CT may be valuable when intravenous urography or
retrograde pyelography is unsuccessful. Pre- and postcontrast
CT may also be useful for distinguishing
enhancing tun10r from a nonopaque calculus.
+ SUGGESTED READING
Baron RL, McClennan BL, Lee TKT, et al. Computed tomography
of transitional cell carcinoma of the renal pelvis and ureter.
Radiology 1 982;144 : 1 25-130.
Pollack HM. Long-term follow-up of the upper urinary tract for
transitional cell carcinoma: How much is enough? Radiology
1988; 1 67:871-872.

Front 85

A 63-year-old woman status post abdominal aortic aneurysm repair presents with
abdominal pain, fever, leukocytosis.

Back 85

Renal abscess: Renal abscesses tend to present as
more focal, well-rounded areas of low attenuation producing
a focal contour abnormality of the kidney.
Typically, there will be enlargement of the involved
kidney with perinephric inflammatory changes. The
low attenuation in the left psoas muscle and adjacent
left perinephric inflammatory change could be due to
either a psoas abscess or postoperative hematoma.
• Renal neoplasm: A renal neoplasm may contain areas
of decreased attenuation due to tumor necrosis.
However, a renal neoplasm would be more mass-like,
deforming the renal contour. If possible, measuring
the attenuation values of a focal mass before and after
contrast material administration is useful.
• Renal infarction: The segmental pattern of involvement
with curvilinear renal subcapsular enhancement
of the right kidney is most consistent with renal infarction.
The clinical scenario of recent abdominal aortic
aneurysm repair with graft placement also suggests this
as the most likely diagnosis. The changes in the left
kidney are most consistent with ischemia or acute
tubular necrosis (AT ). The low attenuation within
the left psoas muscle and left perinephric stranding
may be postoperative in nature, indicative of
hematoma or seroma. This appearance may also be
seen with an aneurysmal leak.
• Acute pyelonephritis: The abnormal persistent nephrogram
of the left kidney as well as the left perinephric
inflammatory changes with low attenuation in the left
psoas may be indistinguishable from severe acute
pyelonephritis. However, one might expect more diffuse
enlargement of the left kidney. Pyelonephritis typically
has a segmental distribution, as is the case within the
right kidney; however, the curvilinear enhancement in
the subcapsular right renal cortex argues for renal infarction
due to the presence of capsular collaterals.
+ DIAGNOSIS: Renal infarction.
+ KEY FACTS
CLINICAL
• Renal infarction typically presents with sudden onset of
severe flank. pain, fever, and hematuria. Nausea and
vomiting are seen in 50% of patients.
• The clinical and laboratory findings, although consistent
with renal infarction, are nonspecific and often
177
suggest alternative diagnoses, including an acute surgical
abdomen.
• Renal infarction may be secondary to complications of
atherosclerotic disease, with resultant thrombosis or
embolic occlusion of the renal artery, typically at the
renal ostia. Post-traumatic dissection of the renal
artery with subsequent thrombosis may also result in
renal infarction.
,
• Iatrogenic causes include prolonged cross-clamp time
from abdominal aneurysm repair. An aortic dissection
may also extend into the abdominal aorta and involve
the renal ostia. This more commonly involves the left
kidney.
• Laboratory findings include moderate leukocytosis and
albuminuria in most cases, and microscopic hematuria
in 50% of cases.
RADIOLOGIC
• The differential diagnosis for a striated nephrogram
includes acute pyelonephritis, renal contusion, renal
vein thrombosis, and ureteral obstruction.
• The subcapsular rim sign is helpful in establishing a
diagnosis of renal infarction. This sign is the result of collateral
flow to the capsular plexus, which supplies the
outer 2 to 4 mm of cortical rim via perforating branches.
• The subcapsular rim sign is not pathognomonic of
renal arterial infarction, because it may also be seen in
renal vein thrombosis and ATN . This pattern of subcapsular
enhancement, however, serves as a crucial distinguishing
feature in the differential diagnosis
between infarction and pyelonephritis.
• The subcapsular or cortical rim sign should not be
confused with the rim or shell nephrogram of
hydronephrosis.

Front 86

A 50-year-old man has back pain and an elevated serum creatinine

Back 86

Malignant retroperitoneal fibrosis (RPF): Imaging
cannot differentiate malignant from nonmalignant
RPF reliably; however, malignant RPF tends to be
more heterogeneous on T2-weighted images.
• Malignant lymphadenopathy and lymphoma: These
entities tend to displace the aorta anteriorly, away from
the spine.
• Idiopathic RPF: The periaortic distribution and signal
characteristics are classic for this entity.
DIAGNOSIS: Idiopathic (nonmalignant)
retroperitoneal fibrosis.
+ KEY FACTS
CLINICAL
• RPF is a rare disorder in which a fibrotic plaque encases
the aorta and extends laterally to engulf the inferior
vena cava ( IVC) and ureters. It usually begins near the
aortic bifurcation and extends cephalad to the renal
hila. Occasionally, it may extend cranially into the
mediastinum or anteriorly into the mesentery.
• At the time of diagnosis, 70% of patients are 30 to 60
years of age.
• Symptoms are nonspecific and include dull back pain,
fatigue, and weight loss. Laboratory values include elevated
serum creatinine levels and erythrocyte sedimentation
rates.
• Two-thirds of cases are idiopathic ( Ormond's disease ) .
The presumed mechanism i s autoimmune, likely a
response to leakage of ceroid, an insoluble lipid, from
atherosclerotic plaques into periaortic tissue. Twelve
percent of cases are secondary to methysergide administration;
beta blockers, hydralazine, methyldopa, and
bromocriptine have also been implicated. Other causes
include malignancy, hemorrhage, and aneurysms (socalled
perianeurysmal fibrosis) .
• Malignant RP F i s a n intense desmoplastic response to
retroperitoneal metastases from a variety of primary
malignancies ( breast, lung, thyroid, gastrointestinal
tract, genitourinary tract, and Hodgkin's lymphoma).
There are only scattered malignant cells, and thus deep
surgical biopsy is required to differentiate benign from
malignant RPF.
• Histologically, perianeurysmal fibrosis (also referred to
as an inflammatory aneurysm ) is identical to RPF. The
only difference is the caliber of the aorta.
• RPF usually results in ureteral dilatation by impairing
peristalsis, rather than direcdy invading the ureter.
• RPF may obstruct the IVC and, rarely, dle portal vein
or common bile duct.
• Treatment consists of a combination of surgery to
release the ureters (ureterolysis) and steroids.
• RPF has a similar histology and is associated with odler
systemic sclerosing diseases, including sclerosing cholangitis,
orbital pseudotumor, mediastinal fibrosis, and
179
Riedel's thyroiditis. There is also an association with
other immune-mediated connective tissue disorders such
as ankylosing spondylitis, Wegener's granulomatosis, systemic
lupus erythematosus, Raynaud's disease, polyarteritis
nodosa, and systemic vasculitis. RPF is associated
with dle major histocompatibility complex HLA-B27.
RADIOLOGIC
• On intravenous urography there is hydronephrosis
widl medial deviation of the middle third of the
ureters, which then taper near dle L4-5 level. This is
in contrast to most cases of lymphoma and other causes
of lymphadenopathy, which are not associated with
a desmoplastic response and thus cause lateral deviation
of the ureters due to mass effect.
• On CT, a homogeneous mande of soft-tissue
envelopes, but does usually not displace, the aorta. It
extends laterally to involve the IVC and ureters, but
usually does not extend > 1 em lateral to the ureters. It
may obstruct the gonadal vessels. The margins are usually
sharply circumscribed and not nodular. However,
it may be ill-defined, although the margin characteristics
cannot be used to distinguish benign from malignant
RPF reliably. Precontrast, it is isoattenuating with
the psoas muscles. Postcontrast, the soft-tissue mass
enhances uniformly, although enhancement din1inishes
with the chronicity of the disease .
• On ultrasound, a homogeneous hypoechoic perivascular
mande is characteristic.
• Widl MR!, the soft-tissue mass is relatively homogeneous
on all imaging sequences. It is isointense to
psoas muscle on T l -weighted images. The signal
intensity on T2-weighted images and the enhancement
on T 1 -weighted images post-gadolinium-chelate
administration vary with the stage . Early in the disease,
dle cellular nature of the infiltrate results in high signal
intensity on T2-weighted images and discernible contrast
enhancement. Late in the disease, the signal
intensity on T2-weighted images and contrast enhancement
decreases, reflecting the fibrotic process. Heterogeneous
high signal intensity on T2 -weighted images
suggests malignancy, while lilliformly low signal suggests
late-stage benign disease.

Front 87

A 67-year-old woman who was previously healthy presents with a 6-week history of
epigastric pain.

Back 87

DIFFERENTIAL DIAGNOSIS
• Renal carcinoma: The mass is separate from the kidney;
therefore this diagnosis is excluded.
• Pheochromocytoma: These tumors usually show very
high signal on T2-weighted images. They are usually
>3 cm and are frequently necrotic and hemorrhagic.
Inferior vena cava ( IVC) invasion, however, is not a
feature of pheochromocytomas.
• Adrenal metastasis: Tumors >5 cm are more likely
malignant. Furthermore, metastases are usually of higher
signal intensity than adenomas. Apart from an adrenal
metastasis in a patient with renal cell carcinoma, IVC
invasion by an adrenal metastasis would be W1Conm10n.
The kidneys show no evidence of tumor in t1us case.
• Adrenal adenoma: This diagnosis is extremely unlikely
unless IVC thrombosis is coincidental.
• Adrenal carcinoma: Although these tumors typically
are larger at presentation, direct IVC invasion makes
this the most likely diagnosis.
+ DIAGNOSIS: Adrenal carcinoma with inferior
vena cava invasion.
+ KEY FACTS
CLINICAL
• Adrenal carcinomas are rare malignant tumors with an
annual incidence of 0 . 5 to 2 . 0 cases per million per year.
• The average age in one large study was 47 years.
• There is a slight female preponderance.
• In a series of 1 56 cases, 5 3% had a functional endocrine
syndrome . Cushing's syndrome is the most common,
with virilization, hypertension, and femiluzation
occurring less frequently.
• Up to 5% of cases are bilateral.
RADIOLOGIC
• Adrenal carcinomas tend to be large at presentation,
usually >5 cm in diameter. Functional tumors tend to
181
be smaller at presention than nonfunctioning tumors.
The range of sizes in one study was 3 to 30 cm, with a
mean diameter of 1 2 cm.
• The problem with small adrenal carcinomas is that it is
often impossible to differentiate benign from malignant
tumors. Tumors >5 cm are more likely malignant,
while evidence of local invasion into adjacent organs or
distant metastases are features of malignant tumors.
• In recent studies, metastases from adrenal carcinoma
were present in 22%, while older studies reported
higher incidences of metastases. The most common
sites are liver, lymph nodes, bone, and lungs.
• Areas of necrosis, hemorrhage, and calcification are
common. The latter is best detected by CT and found
in approxinutely 3 0% of cases.
• By MR!, adrenal carcinoma shows low signal intensity
on T 1 -weighted images and signal intensity greater
than liver on T2-weighted images. Pheochromocytomas
tend to have very high signal intensity on
T2-weighted images and can be difficult to distinguish
from adrenal carcinomas with MRI. Detection and
delineation of vascular invasion, as well as multiplanar
capability, make MR! a useful diagnostic tool in cases
of adrenal carcinoma.
• SUGGESTED READING
Dunnick NR. Adrenal carcinoma. Radiol Clin North Am
1994 ;32 :99-1 08.
Icard P, Chapuis Y, Andreassian B, et aI. Adrenocortical carcinoma
in surgicalIy treated patients: A retrospective study on 1 56 cases.
French Assoc Endocrine Surg 1992 ; 1 1 2 :972-980.
Zografos GC, Driscoll DL, Karakousis CP, Humen RP. Adrenal adenocarcinoma:
A review of 53 cases. Surg Oncol
1994;5 5 : 1 60-164.

Front 88

A 46-year-old man presents with urinary frequency

Back 88

DIFFERENTIAL DIAGNOSIS
• Transitional cell carcinoma (TCC): TCC must be
included in the differential diagnosis of this lesion, but
some features mitigate against this as the most likely
diagnosis. Large intravesical transitional cell Ulmors are
frequently of the papillary variety. They have a stippled
surface and are unlikely to appear as smooth, as in this
case. The location will dictate whether a large lesion of
this size will obstruct the ureter. In this case, no
ureteral obstruction was present.
• Hematoma or fungus ball: There are a multitude of
nonfixed filling defects that can occur witllin the bladder.
It is useful in cases where hematomas or fungus balls are
being considered to image the patient using ultrasound
to document that these are not fixed to the bladder wall.
While ultrasound was not performed in this patient, it is
essential to document whether filling defects within the
bladder are likely to be mobile or fixed.
• Bladder calculus: All urinary calculi are hyperattenuating
on CT ( > + 1 00 Hounsfield wuts [ H U ] ) . This filling
defect measured soft-tissue attenuation.
• Cystitis: Bullous cystitis can appear as a bladder wall
lesion. Cystitis glandularis is a proliferative lesion in
which glandular elements of the bladder mucosa occur
in the submucosa. Many patients have infections and
associated cystitis cystica. These masses are typically villous.
Submucosal fluid-filled cysts describe cystitis cystica,
which can cause filling defects within the bladder.
Chronic infection is postulated as the chief etiologic
factor.
• Bladder leiomyoma: Smooth muscle tumors of the
bladder wall may have this appearance and should be
considered in the differential diagnosis of a smooth
bladder wall filling defect.
DIAGNOSIS: Leiomyoma of the bladder.
KEY FACTS
CLINICAL
183
• Leiomyomas may occur in any site in tl1e genitourinary
tract. These lesions occur in all age groups and affect
both sexes equally.
• Lesions may be endovesical ( 63%), intramural ( 7%), or
extravesical ( 30%).
• The cause of these tumors is unknown.
• The tumor is usually asymptomatic and may be detected
incidentally on physical examination or cystoscopy.
• The endovesical form may present witl1 irritative urinary
symptoms, gross hematuria, or obstructive symptoms.
• Small endovesical lesions can be managed with
transureiliral resection and fulguration . Larger
endovesical, intramural, or extravesical tumors are best
treated with segmental resection.
• The prognosis of this tumor is excellent. No malignant
degeneration has been reported.
RADIOLOGIC
• Intravenous urography or cystography usually reveals a
smooth filling defect within the bladder.
• CT is useful to detern1.ine consistency ( attenuation),
size, location, and possible adjacent organ involvement.
• The endovesical form can be sessile or pedunculated
on cystoscopy and is usually covered with normal bladder
mucosa.
• SUGGESTED READING
Illescas FF, Baker ME, Weinerth JL. Bladder leiomyoma: Advantages
of sonography over computed tomography. Urol Radiol
1986;8 : 2 1 6-2 1 8 .
Knoll LD, Segura JW, Scheithauer BW. Leiomyoma o f the bladder. J
Urol 1986;1 36:906-908.

Front 89

A 40-year-old man with diabetes mellitus presents with fever, left flank pain, and
pyuria.

Back 89

DIFFERENTIAL DIAGNOSIS
• Renal abscess: This diagnosis is unlikely since the central
area of enhancement indicates viable tissue rather
than liquefactive necrosis.
• Renal cell carcinoma (RCC): This is a possible diagnosis
based on the CT appearance, but the clinical presentation
mitigates against a malignant process.
• Renal infarct: This diagnosis is unlikely because
infarcts are typically wedge-shaped and demonstrate a
thin rim of cortical enhancement.
• Focal xanthogranulomatous pyelonephritis (XGP):
The low-attenuation mass in XGP is typically associated
with renal calculi (particularly staghorn) and a nonfunctional
kidney, neither of which is present in this case.
• Focal bacterial pyelonephritis (preabscess, lobar
nephronia): This is the most likely diagnosis based on
the presence of an enhancing mass in the clinical setting
of pyelonephritis .
+ DIAGNOSIS: Focal bacterial pyelonephritis.
+ KEY FACTS
CLINICAL
• Focal bacterial pyelonephritis (preabscess, lobar
nephronia) represents progression from pyelonephritis
to a more severe infection most commonly seen in
patients who are immunocompromised (i.e., diabetes
or patients on steroids/immunosuppressive therapy) .
• Escherichia coli is the most common infecting organism.
185
• An elevated white blood cell count, pyuria, and bacteremia
may occur.
• Failure to respond to appropriate antimicrobial therapy
can cause pyelonephritis to progress to a renal abscess.
RADIOLOGIC
• Intravenous urography demonstrates a poorly functioning
region of the affected kidney, with focal
swelling and mass effect on adjacent calyces.
• On u1trasow1d, a hypoechoic mass with low-level
internal echoes and attenuation of the ultrasound
beam is present. The mass is poorly marginated, with
disruption of the normal corti co medullary junction.
Central anechoic areas may also be present.
• CT imaging displays a lobar inflammatory mass with
mild contrast material enhancement (20 to 40 HU less
than the surrounding enhanced parenchyma). The
mass is typically irregular, rounded, and heterogenous
in attenuation.
• SUGGESTED READING
Goldman S . Acute and chronic urinary infection: Present concepts
and controversies. Urol Radiol 1988; 1 0 : 1 7-24.
Pollack H. Clinical Urography. Philadelphia: Saunders,
1 990;799-8 1 5 .
Rabushka L, Fishman E , Goldman S . Pictorial review: Computed
tomography of renal inflammatory disease. Urology
1 994;44:473-480.
Zaol1tz M, et al. Acute focal bacterial nephritis: A systematic
approach to diagnosis and treatment. J Urol 1 98 5 ; 1 33 :752-756.

Front 90

A 63-year-old woman has microscopic hematuria

Back 90

DIFFERENTIAL DIAGNOSIS
• Pseudoureterocele: This appearance is caused by a
transitional cell carcinoma (TCC) of the bladder or a
stone obstructing the ureter. It is unlikely because of
the lack of a ftlling defect or mass, as well as the bilaterality
of the defects. Other less common causes of the
"pseudo ureterocele" appearance include cervical carcinoma
invading the ureterovesical orifice, radiation cystitis,
or edema of the ureterovesical junction from
recent stone passage. However, these are unlikely in
this case because the former are identified by asymmetry
of the distal lumen and irregularity of the wall and
generally do not have intravesicular protrusion.
However, they are capable of distending the distal
ureter and thus mimicking an orthotopic ureterocele.
• Bilateral simple ureteroceles: This is the most likely
diagnosis given the lack of a bladder mass or irregularity,
the intravesicular protrusion, the absence of upper
tract dilatation, and the bilaterality.
DIAGNOSIS: Bilateral simple ureteroceles.
+ KEY FACTS
CLINICAL
• An orthotopic ureterocele forms in a ureter with a
normal insertion into the trigone, as opposed to an
ectopic ureterocele .
187
• Orthotopic ureteroceles usually occur in single systems,
as opposed to ectopic ureteroceles, which occur
in duplicated systems.
• Orthotopic ureteroceles are usually unilateral, asymptomatic,
and incidental. However, a calculus may lodge
or form in the ureterocele.
• A ureterocele is a congenital deformity.
• A ureterocele consists of a prolapse of the distal ureter
into the bladder with associated dilation of the distal
ureter.
• The wall of the ureterocele is composed of a thin layer
of muscle between the outer surface of the bladder
uroepithelium and the inner surface of the ureteral
uroepithelium.
RADIOLOGIC
• The typical radiographic appearance is the so-called
"cobra head" deformity, which is formed by the projection
of the minimally dilated distal ureter into the
lumen of the bladder, with opacified urine surrounding
the ureterocele.
• The thin line of radiolucency represents the wall of the
ureterocele.
SUGGESTED READING
Davidson AT, Hartman DS. Radiology of the IGdney and Urinary
Tract (2nd ed). Ph.iladelphia: Sawlders, 1994;520-523.
Mitry HA, Schapira HE. Ureterocele and pseudoureterocele: Cobra
versus cancer. J Urol 1977; 1 1 7:557-561

Front 91

A 54-year-old man presents with abdominal pain.

Back 91

DIFFERENTIAL DIAGNOSIS
• Hemorrhagic renal cell carcinoma (RCC): This
diagnosis is unlikely because the entire lesion is of uniform
increased attenuation on the noncontrast study.
• Angiomyolipoma that has bled: This diagnosis is
wilikely because no fat is demonstrated on the CT examination
to raise the suspicion of an angiomyolipoma.
• Hemorrhagic renal cyst: This is the most likely diagnosis
for a uniform, nonenhancing, high-attenuation
renal mass.
+ DIAGNOSIS: Hemorrhagic renal cyst.
+ KEY FACTS
CLINICAL
• Renal cysts account for approximately 60% of all renal
masses.
• Renal cysts increase in frequency with age ( approximately
50% of cases occur past the age of 50).
• Most renal cysts are asymptomatic, whether hemorrhagic
or not.
• Hemorrhagic cysts are frequently seen in patients with
autosomal dominant polycystic kidney disease and
acquired renal cystic disease.
189
RADIOLOGIC
• Noncontrast CT is absolutely necessary to evaluate the
attenuation of the lesion before contrast material
administration.
• Cysts that are "hyperdense" exhibit attenuation values
between +50 and +90 HU. The high attenuation is
due to a high content of protein, blood breakdown
products, or iodine. To be considered a benign hyperdense
cyst, the lesion must be sharply marginated,
homogeneous, and nonenhancing ( < l 0 HU increase
postcontrast).
• Because of tl1e tluckness of the wall and the internal
structure of the lesion, these cysts carmot be evaluated
reliably with ultrasound, and only 50% of hyperattenuating
lesions demonstrate typical sonographic cyst criteria.
CT is necessary, particularly to evaluate for
potential lesion enhancement.
+ SUGGESTED READING
Bosniak MA. The small (s3.0 em) renal parenchymal tumor:
Detection, diagnosis, and controversies. Radiology
1 99 1 ; 1 79:307-3 1 7 .
Bosniak MA. Problems in the radiologic diagnosis o f renal parenchymal
tumors. Urol Clin North Am 1993;20: 2 1 7-230.
Curry NS. Small renal masses ( lesions smaller than 3 em): Imaging
evaluation and management. AJR Am J Roentgenol 1995; 1 64:
3 5 5-362

Front 92

A 33-year-old man has a history of urinary tract infections.

Back 92

Retroperitoneal mass with displacement of the kidney:
While a retroperitoneal mass can cause displacement
of the kidney, the size of a mass required to displace
the kidney into the opposite side of the abdomen
would be quite large. One would expect such a mass
to be obvious on physical examination.
• Renal duplication with agenesis of the contralateral
kidney: Renal duplication would explain an enlarged
kidney and would account for the presence of two
ureters. However, noting that the ureter crosses into
the opposite hemipelvis to enter in its normally expected
location in the trigone excludes tills diagnosis.
• Crossed renal ectopia: This is the most likely diagnosis
given the position of the kidneys and the insertion
of the ureters.
DIAGNOSIS: Crossed renal ectopia.
KEY FACTS
CLINICAL
• There are four types of crossed renal ectopia:
1 . Crossed renal ectopia with fusion.
2. Crossed renal ectopia without fusion.
3. Solitary crossed renal ectopia: In tills case, there is
only one kidney, which lies in the abdomen opposite
from the side of its ureteral insertion .
4. Bilateral crossed renal ectopia: In tills case, both
kidneys are crossed to the opposite side of the
abdomen with their ureters inserting into the contralateral
ureterovesicle junction.
5. The most common varieties are fused and unfused
ectopia; crossed fused ectopia occurs in 85% to 90%
of cases.
• Crossed renal ectopia is seen more commonly in males
than females.
• The most common scenario is the left kidney crossing
to the right side of the abdomen.
191
• There are associated urinary tract abnormalities, including
obstruction, stones, infection, vesicoureteral reflux,
primary mega-ureter, hypospadius, cryptorchidism, urethral
valves, and multicystic dysplastic kidney.
• There are associated abnormalities of other organ systems,
including skeletal anomalies, unilateral ovarian
and fallopian tube agenesis, and cardiac and gastrointestinal
anomalies.
• Theories of occurrence include faulty development of
the ureteral bud with crossing of the midline to contact
the contralateral metanephric blastema, obstruction of
renal ascent by blood vessels, and local environmental
factors involving surrOlmding tissues and organs.
RADIOLOGIC
• The most common scenario is crossed fused ectopia.
Radiographically tills can be diagnosed on either ultrasound,
CT, or intravenous urography when renal tissue
lies on the opposite side of the abdomen from its
ureteral insertion, and renal tissue from the crossed
kidney fuses with the kidney native to that side of the
abdomen. Spiral CT, particularly using coronal reformation,
or MRl may be useful in distinguishing fused
from unfused ectopia.
• CT is also useful in establishing that a case of crossed
ectopia is in fact a congenital abnormality and will help
to exclude the presence of a retroperitoneal mass causing
mass effect with renal displacement.
• Patients with this abnormality are usually asymptomatic,
although they may present with a palpable abdominal
mass or a history of urinary tract infection(s).
• SUGGESTED READING
Silva JM, Jafri SZH, Cacciarelli AA, et a1. Abnormalities of the kid·
ney: Embryogenesis and radiologic appearance. Appl Radiol
1995;24 : 1 9-24.

Front 93

A 60-year-old man presents with a palpable right-sided abdominal mass, flank pain,
and hematuria.

Back 93

Renal cell carcinoma (RCC): The imaging features in
this case reveal the presence of a solid, enhancing right
renal mass with features that are consistent with RCC.
The broad area of low attenuation within the mass
could represent internal hemorrhage or necrosis.
• Oncocytoma: There are no imaging features that confidently
allow for tl1e cliagnosis of a benign oncocytoma.
However, this cliagnosis belongs in the differential
cliagnosis of a solitary renal mass in a patient who
has no evidence of metastatic clisease (no retroperitoneal
lymphadenopathy and no osseous, hepatic, or
pulmonary parenchymal metastases) .
• Renal metastasis: I f this patient had a history of a
known primary malignancy, particularly in the lung,
breast (this patient is a male) , or colon, a renal metastasis
would be a possibility. A percutaneous biopsy
could be performed for further tissue cliagnosis. No
such history existed in this patient.
• Angiomyolipoma: The cliagnosis of angiomyolipoma
is made when fat is detected within a renal mass. It is
possible that given sufficient hemorrhage within an
angiomyolipoma no fat may be detected. Similarly, a
small amount of fat may be present within an
angiomyolipoma that cannot be detected unless thin
sections are obtained. No fat was detected within this
mass, and there was no evidence of subcapsular or perinephric
hemorrhage.
• Lymphoma: This patient has no history of nonHodgkin's
lymphoma. Furthermore, no retroperitoneal
lymphadenopathy is present, although lymphomatous
masses may exist within the kidneys in the
absence of lymphadenopati1y.
+ DIAGNOSIS: Renal oncocytoma.
+ KEY FACTS
CLINICAL
• An "oncocyte" is a transformed epiti1elial cell with an
enlarged, homogeneous, dense cytoplasm filled with
acidophilic granules.
• Microscopically, a renal oncocytoma is characterized by
eosinophilic epithelial cells with protuberant mitochondria
within the cytoplasm.
• A renal oncocytoma has a clistal tubular or collecting
duct origin.
• On gross examination, lesions are well circumscribed,
often encapsulated, without necrosis or hemorrhage . A
central stellate scar may be present.
• The right kidney is affected as often as the left kidney.
Cases of bilateral synchronous tumors have been
reported.
193
• The tumor size ranges from 0 . 1 to 26.0 cm.
• The age at cliagnosis ranges from 26 to 94 years.
• There is a 1 .63 to 1 .0 male-to-female ratio.
• Less than one-tlllrd of patients will present with the classic
triad of a palpable mass, flank pain, and hematuria.
• Renal oncocytoma exhibits a limited, although real,
potential for malignancy or metastasis.
RADIOLOGIC
• Ultrasound shows a homogeneous, iso- to hyperechoic,
well-marginated mass. These are inclistinguishable
from RCC.
• Angiographic features include a "spoke-wheel" appearance
to the internal vascular architecture. These lesions
have a dense parenchymal blush and lack angiographic
features of contrast meclia puddling, arteriovenous shunting,
or renal vein invasion (all characteristics of RCC).
• On CT, ti1ese lesions have a clistinct margin and
smooth contour, with or without a central stellate scar.
The lesions enhance homogeneously.
• A study performed to clifferentiate renal oncocytoma
from RCC showed that among oncocytomas >3 cm,
67% exhibit criteria for oncocytoma ( homogeneous
attenuation ti1roughout the tumor, a central, sharply
marginated stellate area of low attenuation), while 33%
met the criteria for adenocarcinoma. Among smaller
oncocytomas, 82% met the criteria for oncocytoma, and
1 8% met the criteria for adenocarcinoma. CT, therefore,
is a poor preclictor of the cliagnosis of oncocytoma.
• On MRl, oncocytomas are of homogenous, low signal
intensity on T1 -weighted images and high signal intensity
on T2-weighted images. The presence of a capsule
or a central stellate scar and the absence of either internal
hemorrhage or necrosis also favor this cliagnosis.

Front 94

A 48-year-old man was referred for CT after seeing his ophthalmologist.

Back 94

Multiple renal cell carcinomas ( RCCs) in a patient
with von Rippel-Lindau disease (VHL): The constellation
of bilateral renal enlargement with multiple
solid and cystic lesions in combination with solid and
cystic pancreatic lesions is virtually diagnostic of VHL.
The patient was seeing the ophthalmologist because of
a retinal angioma.
DIAGNOSIS: von Rippel-Lindau disease with
multiple renal cell carcinomas.
+ KEY FACTS
CLINICAL
• VHL is characterized by retinal angiomas, central nervous
system hemangioblastomas, cystic and solid
tumors of the pancreas, pheochromocytomas, renal
cysts, and RCCs.
• Inheritance follows an autosomal dominant pattern.
Clinical situations leading to a suspicion of VHL
include a family history of VHL, pheochromocytoma
or RCC, an epididymal cystadenoma, bilateral multifocal
RCC, bilateral multifocal renal cysts, bilateral
pheochromocytomas, an RCC in a patient <30 years of
age, pancreatic cysts, multiple hemangioblastomas of
the central nervous system, and retinal angiomas.
• Early symptoms are usually caused by cerebellar and
retinal tumors.
• Renal involvement is characterized by multiple bilateral
cysts and RCCs. The mean age of presentation of RCC
is approximately 39 years; this is 20 years younger than
the mean age for the discovery of sporadic RCC. RCC
in VHL has a slight male predominance.
RADIOLOGIC
• RCC has been reported to occur in 28% to 45% of patients
with VHL. Renal cysts are present in 59% of patients,
renal adenomas in 14%, and retinal angiomas in 7%.
• Renal involvement is characterized by multiple bilateral
cysts and RCCs.
• Renal involvement in VHL is multicentric and bilateral
in up to 75% of patients.
• Renal cysts in VHL may occur as simple cysts or complex
papillary projections into cystic lumina. Small
nodules of tumor may be found in the walls of cysts.
Cysts may grow, typically at a rate of 0.5 cm/year;
other cysts involute over time, leaving small scars on
the renal surface. Extensive cystic disease in VHL can
mimic autosomal dominant polycystic kidney disease.
195
• RCCs in patients with VHL grow at the rate of 0 . 2 to
2 . 2 cm/year, which is faster than patients observed
with sporadic RCC.
• CT is more sensitive for small lesions « 2 c m) . Thin
section, contrast-enhanced CT is mandatory for the
evaluation of renal lesions in patients with VHL .
• Yearly radiographic imaging i s recommended t o survey
for renal lesions.
• An approach to renal lesion management is to wait
until solid lesions obtain a size of 2 to 3 cm, and then
perform nephron-sparing surgery. After surgery is performed,
close follow-up is recommended. CT scanning
every 6 months for 2 years, followed by lifetime annual
screening, has been advocated.
• Approximately 7% to 1 8% of all patients with VHL
have pheochromocytomas. Pheochromocytomas when
associated with VHL are often multiple and ectopic;
approximately 50% to 80% are bilateral.
• Pancreatic lesions also occur in the setting of VHL,
including pancreatic cysts, serous microcystic adenomas,
and adenocarcinomas. Cysts are present throughout
the pancreas and have no predilection for a particular
site. Lesions range from several millimeters in size
to > 1 0 cm.
• A serous cystadenoma is a grape-like cluster of multiple
microscopic and macroscopic cysts separated by thickened
walls of stroma. There may be a central nidus,
which may be calcified or scar-like.
• Cysts and cystadenomas of the pancreas are benign in
patients with VHL and need not be removed .
• Additional lesions present in a patient with VHL
include papillary cystadenomas of the epididymis ( 1 0%
to 26% of men with VHL). Epididymal cystadenomas
can be unilateral or bilateral and are often found in the
globus major. Lesions range in size from 1 to 5 cm but
are typically 2 to 3 cm.

Front 95

A 41 -year-old man involved in a motor vehicle accident presents with microscopic
hematuria.

Back 95

Renal contusion: A renal contusion can be diagnosed
as a hypoperfused area on postcontrast CT. There may
be subtle changes in the perirenal fat and subcutaneous
tissues to indicate a traumatic injury.
• Renal laceration: A renal laceration appears as a linear
defect in the nephrogram on the CT evaluation.
Lacerations may be either minor or major. A minor
laceration does not extend to the level of the collecting
system, whereas a major laceration involves the collecting
system. A minor laceration will most often be
accompanied by a perirenal hematoma; a major laceration
is accompanied by both hematoma and urinoma.
• Renal fracture: A renal fracture is diagnosed when
there is cleavage of the kidney into two separate portions.
These injuries often occur along planes that
spare renal vasculature; therefore, enhancement is seen
in both portions of the fractured kidney.
• Subcapsular hematoma: A subcapsular hematoma is
identified as a fluid collection contained within the
renal capsule. This is easily diagnosed on noncontrast
CT as a high-density fluid collection.
• Renovascular injury: Renovascular injuries are identified
by nonenhancement of the kidney. Absence of the
nephrogram is referred to as a negative CT nephrogram.
Loss of the pyelogram postcontrast is called a
negative CT pyelogram. Arterial renal vascular injuries
may be secondary to thrombosis or laceration; thrombosis
is more common. Given appropriate imaging,
cut-off may be seen in the renal artery after a bolus of
contrast material, tl1e so-called "renal artery cut-off
sign.)) Renal vein injuries tend to be lacerations as
opposed to tllrombotic in nature. In these cases, large
retroperitoneal hematomas can occur without significant
renal parenchymal injury.
• DIAGNOSIS: Renal laceration with perinephric
hematoma/urinoma.
KEY FACTS
CLINICAL
• Hematuria may be found in patients with injury to the
genitourinary system, as well as in patients with intraabdominal
injury not related to the genitourinary system.
The degree of hematuria does not reflect the
severity of the injury. Furthermore, patients may have
severe injury to the genitourinary system, including a
renal pedicle injury, without the presence of hematuria.
• Traumatic injury to the kidney may cause a renal laceration
or fracture, a contusion, a subcapsular hematoma,
197
or a renovascular injury. Although many renal injuries,
such as contusions or minor lacerations, are managed
conservatively, surgery is generally indicated in patients
with a shattered kidney or a renovascular injury.
RADIOLOGIC
• A contrast-enhanced CT of the abdomen and pelvis is
the single best imaging modality to evaluate the nature
and extent of renal injury in the trauma setting.
However, if renal vascular injury is suspected and the CT
is negative or equivocal, angiography may be required.
• Renal contusion is manifest as a focal area of renal
parenchyma that does not enhance to the degree of
normal renal parenchyma, without evidence of laceration
or fracture.
• A renal laceration is a focal parenchymal tear, demonstrated
as an area of decreased attenuation within the
renal parenchyma, as in this case. The tear often
extends to involve the collecting system, resulting in
extravasation of blood and urine into the perinephric
space. In the early phase of contrast media excretion,
the perinephric fluid may be of relatively low attenuation.
Delayed images, however, are very helpful in confirming
extravasation, because there will be progressive
opacification of this fluid.
• A renal fracture implies cleavage or transection of the
kidney into two poles, with extravasation of blood and
urine.
• A shattered kidney denotes multiple fractures or
fragments.
• On CT, a subcapsular hematoma is seen as a highattenuation
fluid collection in the perinephric region,
often lenticular in shape, that may cause mass effect or
flattening of the renal cortex.
• A renal vascular injury may be identified by extravasation
of venous or arterial contrast material, or as focal or
global areas of nonenhancement of renal parenchyma

Front 96

A 52-year-old Asian woman presents with left flank pain.

Back 96

DIFFERENTIAL DIAGNOSIS
• Complicated renal cyst of the left upper pole: The
water attenuation of the lesion fits for a simple cyst;
however, the perceptible wall excludes the diagnosis of
a simple cyst. A cyst that is infected or hemorrhagic
could have this appearance.
• Cystic renal cell carcinoma (RCC): Some RCCs are
cystic; others can measure in the range of water attenuation
due to extensive necrosis or hemorrhage.
• Renal abscess: An infection within the kidney that has
liquefied could have this appearance. It is helpful in
these cases to correlate imaging findings with urinalysis,
as well as possible clinical symptoms such as pyrexia,
leukocytosis, and flank pain.
• Ureteral duplication with obstruction of the upper
pole moiety: This diagnosis can be made due to the
presence of the fluid attenuation tubular structure
adjacent to the left ureter. This tubular structure may
be confused with a thrombosed gonadal vein, and
therefore its path must be followed. If this tubular
structure enters the left renal vein, a thrombosed
gonadal vein can be diagnosed. If this tubular structure
is in continuity with the cystic upper pole mass,
the diagnosis of an obstruction duplicated system can
be made with confidence. This will subsequently be
confirmed by cystoscopy, with the identification of two
ureteral orifices on this side.
+ DIAGNOSIS: Obstruction of the upper pole collecting
system in complete ureteral duplication.
+ KEY FACTS
CLINICAL
• Patient with obstruction of the upper pole moiety may
present with nonspecific abdominal pain; this is the
most common factor leading to clinical evaluation.
199
• Alternatively, patients may present with lower tract
signs and symptoms related to the ectopic insertion of
the duplicated ureter--e.g., incontinence.
• Otller presentations may be related to obstruction of
the upper pole moiety and the presence of calculus disease
( hematuria) or stages of urine ( infection ) .
RADIOLOGIC
• Duplication anomalies of the kidney are common. In
patients with a completely duplicated system, both
ureters may insert orthotopically; however, the ureter
arising from the upper pole moiety frequently inserts
ectopically either intravesically or extravesically.
Patients most often present with symptoms related to
upper pole obstruction or lower pole reflux.
• Imaging is useful for documenting the presence of
complete duplication and whether the upper pole is
obstructed. CT is useful for evaluating the amount of
residual parenchyma in the upper pole. Cystography is
frequently used to docunlent reflux. Ultrasound can
image the obstructed upper pole but usually Carulot
image the entire ureter.
+ SUGGESTED READING
Cramer BC, Twomey BP, Katz D . CT findings in obstructed upper
moieties of duplex kidneys. J Comput Assist Tomogr 1983;
7:25 1-2 5 3 .
Cronan JJ, Amis E S , Zeman RK, Dorfman G S . Obstruction o f the
upper-pole moiety in renal duplication in adults: CT evaluation.
Radiology 1986; 1 6 1 : 1 7

Front 97

A 48-year-old woman is referred for renal ultrasound following a urinary tract infection

Back 97

Renal cell carcinoma ( RCC): Approximately 30% of
small RCCs are markedly hyperechoic. The presence of
either small intratumoral cyst or an anechoic rim can
suggest RCC. Thin-section CT must be performed for
characterization of a hyperechoic mass. Fat-containing
RCCs with osseous metaplasia have also been reported,
although they are extremely rare . RCCs can also
contain low attenuation of foci due to lipid-producing
necrosis. These tumors contain lipid vacuoles and
amalgamated cholesterol clefts. An RCC can also grow
by extension and entrap perirenal fat. RCCs that
behave in this fashion tend to be large, >5 cm in diameter,
and have irregular margins.
• Lipoma: A lipoma is a rare benign tumor of the kidney
composed of adipose tissue.
• Liposarcoma: A renal liposarcoma is usually located
peripherally, beneath the renal capsule. The tumor is
large and bulky and extends into the perirenal space.
• Fat-containing renal oncocytoma: Fat may be present
within an oncocytoma that grows sufficiently large
to entrap perirenal or sinus fat.
• Adrenal myelolipoma: A full examination of ultrasound
and CT images should help distinguish a fatcontaining
adrenal mass from a fat-containing renal
mass. MRI with sagittal and coronal imaging may
improve the ability to distinguish a renal angiolipoma
from an adrenal myelolipoma.
• Renal angiomyolipoma (AML): This is the most
likely diagnosis for a fat-containing renal mass.
+ DIAGNOSIS: Renal angiomyolipoma (AML).
+ KEY FACTS
CLINICAL
• AMLs are benign hamartomas composed of fat,
smooth muscle, and blood vessels.
• Eighty percent of AMLs are solitary; they occur sporadically,
and they are most common in women 40 to
60 years of age.
201
• Twenty percent are multiple and bilateral, usually in
association with tuberous sclerosis.
• These tumors are usually an incidental finding.
• Hemorrhage may occur when lesions are large, producing
hematuria, flank pain, and in severe cases,
shock.
• Treatment of AMLs includes embolization or resection,
especially if the AML is >4 em in diameter, to
avoid the threat of spontaneous hemorrhage.
RADIOLOGIC
• Plain films may reveal subtle lucencies due to fat content;
however, this finding is seen in < 1 0% of cases.
Calcifications are seldom seen, and when present, suggest
an RCC.
• Intravenous urography reveals a nonspecific mass,
which is frequently exophytic.
• Ultrasound demonstrates a well-demarcated, highly
echogenic renal mass, although echo-poor areas may
be seen due to internal necrosis or hemorrhage, particularly
in larger tumors.
• On CT, either with or without contrast material, the
presence of fat « - 1 0 HU) is virtually diagnostic. In
some AMLs, however, the fat is microscopic, and
because of partial volume averaging, no fatty attenuation
will be appreciated.
• With angiography, 95% of the tumors are hypervascular,
with dilated arteries. Angiography, however, is
rarely performed unless embolization is anticipated.
• On MR!, there is variable high signal intensity on T l weighted
images and intermediate signal intensity on
T2-weighted images depending on the fat content.

Front 98

A 60-year-old man has a palpable abdominal mass on the left.

Back 98

DIFFERENTIAL DIAGNOSIS
• Renal abscess: One would expect appropriate symptomatology
in a patient with an abscess of this size. A
thickened wall that enhances can be seen in a renal
abscess. However, lack of inflammatory changes in the
perinephric fat may suggest other diagnostic possibilities.
• Hemorrhagic cyst: Over time the attenuation within a
hemorrhagic renal cyst may decrease, causing an old
hemorrhagic cyst to have a more cystic appearance.
The eccentric, lateral wall prominence that enhances,
however, prevents one from calling this lesion a hemorrhagic
cyst.
• Cystic RCC: This is the most likely diagnosis for a
cystic renal mass with an enhancing mural nodule.
DIAGNOSIS: Cystic renal cell carcinoma,
Bosniak type 4 lesion.
KEY FACTS
CLINICAL
• Patients with RCC may present with the classic triad of
pain, mass, and hematuria.
• Other symptoms include fatigue, malaise, anorexia,
weight loss, fever, and anemia.
• Men are most commonly afflicted, with a male-tofemale
ratio of 2 to 1 .
• Patients are typically in the sixth to seventh decade.
RADIOLOGIC
• A Bosniak type 4 cyst is one that clearly has malignant
features as well as large cystic components. Lesions in
this category show irregular margins and solid enhanc-
203
ing elements. They are clearly malignant and should be
treated surgically.
• Cysts are sometimes complicated by the presence of
calcifications, septations, abnormal attenuation, wall
thickening, or nodularity. A solid nodule within a cyst
lumen that enhances is a feature that indicates the
presence of a malignancy with high reliability.
Vascularity within the nodule combined with nodular
thickening of a cyst wall is also a clear indication of
malignancy.
• This lesion should not be classified as a Bosniak type 3
lesion. Type 3 cysts exhibit some of the features of
malignant lesions and radiographically cannot be distinguished
from malignancy. Resection is necessary to
distinguish a benign from a malignant lesion.
• A multilocular cystic nephroma is a benign Bosniak
type 3 lesion, while a multicystic RCC is a malignant
Bosniak type 3 lesion. These two tumors may be indistinguishable
radiographically.
SUGGESTED READING
Bosniak MA. The current radiological approach to renal cysts.
Radiology 1986; 1 5 8 : 1 - 1 0 .
Dalla-Palma L , Pozzi-Mucelli F , Donna AD, Pozzi-Mucelli RS .
Cystic renal tumors: U S and C T fIDdings. Urol Radiol
1990 ; 1 2 :67-73.
Parienty RA, Pradel J, Parienty 1. Cystic renal cancers: CT characteristics.
Radiology 1 98 5 ; 1 57:74 1-744.
Rofsky NM, Bosniak MA, Weinreb JC, Coppa GF. Giant renal cell
carcinoma: CT and MR characteristics. J Comput Assist Tomogr
1989; 1 3 : 1 078-1080.
Waguespack RL, Kearse WS Jr. Renal cell carcinoma arising from the
free wall of a renal cyst. Abdom Imag 1996;2 1 :7 1-72.
Wilson TE, Doelle EA, Cohan RH, et al. Cystic renal masses: A
reevaluation of the usefi.llness of the Bosniak classification system.
Acad Radiol 1996;3:564-57

Front 99

A 62-year-old man has a history of chronic urinary tract infections

Back 99

DIFFERENTIAL DIAGNOSIS
• Blood clots: Blood clots can cause multiple ureteral
filling defects. One would expect that the patient
would have an accompanying history of hematuria.
Additional history may be helpful and could include
known bleeding disorders or trauma.
• Multiple ureteral stones: Stones can cause multiple
filling defects, although typically, due to their calcium
content, stones are most often radiopaque. This limits
their detectability on contrasted examinations. The
fixed nature of the filling defects, as seen in this
patient, would make this an unlikely possibility.
• Multiple ureteral transitional cell carcinomas
(Tees): While Tee has a propensity to be multifocal,
this would represent an extremely rare manifestation of
urothelial carcinoma. Correlation should be made with
findings of urine cytology to establish whether malignant
cells are present.
• Ureteritis cystica: This is one of several causes of multiple
ureteral filling defects. Ureteritis cystica is often
seen in the setting of chronic urinary tract infections.
+ DIAGNOSIS: Ureteritis cystica.
+ KEY FACTS
CLINICAL
• Ureteritis cystica is associated with chronic mucosal
irritation secondary to inflammation.
205
• These lesions are secondary to degeneration and cavitation
of metaplastic surface urethelium or submucosal
Brunn's cell nests.
• Patients may be asymptomatic or have hematuria and
symptoms of a urinary tract infection.
• These lesions are not premalignant.
• The lesions may be unilateral or bilateral.
• Females are affected slightly more with ureteritis cystica
than males.
• Patients are typically 50 to 60 years old.
RADIOLOGIC
• Lesions are typically 2 to 3 mm in size, although they
can range from 1 mm to 2 cm in size.
• Lesions are multiple, smooth, well-rounded or oval
filling defects with sharp borders.
• Lesions are said to predominate in the proximal ureter
but may be seen throughout the ureter, in the renal
pelvis (pyelitis cystica), or in the bladder (cystitis cystica).
+ SUGGESTED READING
Frederick MG, Kakani L, Dyer RB. Ureteritis cystica and pseudodiverticulosis
in ureteral stumps. Appl Radiol 1995;24:32-33.
Loitman BS, Clllat H. Ureteritis cystica and pyelitis cystica.
Radiology 1 957;68:345-3 5 1 .

Front 100

A 76-year-old man has benign prostatic hypertrophy and bladder outlet obstruction

Back 100

DIFFERENTIAL DIAGNOSIS
• True ureteral diverticula: True diverticula are typically
large, saccular, round or oval, and usually solitary.
True diverticula fill slowly with contrast material during
an intravenous urogram . Depending on their location,
they may be confused with a hydroureter, a bladder
diverticulum, or a large ureterocele.
• Ureteritis cystica: It is important to recognize that in
ureteritis cystica there are filling defects within the
ureteral lumen. This case demonstrates ureteral outpouchings
as opposed to mural filling defects.
• Ureteral pseudodiverticulosis: The small ureteral
outpouchings present in this patient are virtually
pathognomonic of ureteral pseudodiverticulosis.
+ DIAGNOSIS: Ureteral pseudodiverticulosis.
+ KEY FACTS
CLINICAL
• Ureteral pseudodiverticulosis is associated with urinary
tract infections, obstruction, and stones.
• Patients may present with hematuria or symptoms of a
urinary tract infection.
• Pathologically, these lesions are outpouchings of proliferated
hyperplastic transitional epithelium extending
into loose subepithelial connective tissue.
207
• The lesions do not extend through the muscularis propria;
therefore, they are not true diverticula.
• Fifty percent of patients have atypica on urine cytology.
A similar percentage have or will develop a TCC
( most common site is the bladder) .
RADIOLOGIC
• The outpouchings are small, typically measuring 2 to 4
mm in diameter.
• The outpouching are nearly always multiple, numbering
three to eight lesions per ureter.
• The findings are bilateral in 70% of cases.
• The abnormalities predominate in the proximal and
mid ureter (85% of cases) .
• Retrograde or antegrade urography is better than intravenous
urography, which is positive in only 60% of cases.
+ SUGGESTED READING
Wasserman NF. Pseudodiverticulosis: Unusual appearance for metastases
to the ureter. Abdom Imag 1 994;19: 376-378.
Wasserman NF, Pointe SL, Posalaky IP. Ureteral pseudodiverticulosis.
Radiology 1 98 5 ; 1 5 5 :56 1-566.
Wasserman NF, Zhang G, Posalaky IP, Reddy PK Ureteral pseudodiverticula:
Frequent association with uroepithelial malignancy.
AJR Am J Roentgenol 1 99 1 ; 1 57:69-72 .

Front 101

A 22-year-old man presents with weight loss.

Back 101

DIFFERENTIAL DIAGNOSIS
• Renal metastases: Renal metastases typically arise
from primary cancers of the IWlg, breast, colon, or
melanoma. Renal metastases are usually discovered at
autopsy rather than radiographically. To make a diagnosis
of renal metastases, careful inspection should be
made for potential additional sites of metastatic disease
(lung, liver, adrenals, lymph nodes) as well as determination
of appropriate clinical history.
• Multifoca1 renal cell carcinoma (RCC): While RCC
can be multifocal, particularly in patients with von
Hippel-Lindau disease (VHL), this would be an
uncommon appearance and presentation for this renal
malignancy.
• Lymphoma: The most common presentation of renal
lymphoma is that of bilateral renal masses. This can
occur with or without accompanying retroperitoneal
lymphadenopathy.
• Hemorrhagic renal cysts: Patients with autosomaldominant
polycystic kidney disease often experience
hemorrhage into renal cysts. Clinical history as well as
noncontrast imaging should permit the radiologist to
determine whether the lesions are solid and enhancing
or hemorrhagic.
+ DIAGNOSIS: Renal lymphoma.
+ KEY FACTS
CLINICAL
• Genitourinary lymphoma is most commonly of the
non-Hodgkin's variety.
• Lymphoma involves the genitourinary tract in 1 0% to
50% of cases.
• Of patients with non-Hodgkin's lymphoma, 1 0% to
20% either present with or eventually suffer from genitourinary-
related symptoms.
• Sites of involvement in the genitourinary tract in
descending order of frequency include the kidneys,
testes, bladder, and prostate .
209
• Symptomatically, patients may have vague abdominal
pain, weight loss, fever, night sweats, anemia, and
hematuria. Additional manifestations may include lymphadenopathy,
hepatosplenomegaly, and a palpable
abdominal mass.
RADIOLOGIC
• The most common presentation of renal lymphoma on
CT is bilateral soft-tissue masses ( 6 1 % ) . This can often
occur without accompanying retroperitoneal lymphadenopathy.
• The second most common presentation of renal lymphoma
is that of invasion from retroperitoneal or perinephric
masses.
• A third presentation is that of a single, bulky renal
mass.
• The least common presentation is isolated lymphomatous
disease in the perirenal space.
• Intravenous urography may show enlargement of one
or both kidneys, a localized expanding mass, or masses
with calyceal distortion.
• On ultrasound, lymphomatous masses are typically anechoic
without posterior acoustical enhancement or
hypoechoic.
• MRI may be used in patients in whom iodinated contrast
material cannot be given. The multifocal nature
of the disease process is usually readily apparent, particularly
following the intravenous adn1i.nistration of a
gadolinium-chelate.

Front 102

A I S-year-old boy has a history of urinary tract infections.

Back 102

DIFFERENTIAL DIAGNOSIS
• Right renal "obstruction" secondary to a distal
right ureteral calculus: While a stone with secondary
edema could explain the narrowing of the distal ureter,
the CT clearly shows that there was no delay in
enhancement on the right side, and the "pelvicaliectasis"
is more likely on the basis of congenital megacalyces.
Clinically, the patient did not have renal colic,
nor did he have hematuria.
• Distal right ureteral stricture: While a stricture could
cause narrowing of the distal ureter, the appearance of
the proximal ureter and kidney suggests that there is
no obstruction of the distal ureter.
• Primary megaureter: The fusiform dilatation of the
distal ureter above a narrowed segment is classic for
primary mega ureter. The associated megacalyces on
the right also support this diagnosis.
DIAGNOSIS: Primary megaureter.
KEY FACTS
CLINICAL
• Primary mega ureter has also been called megaloureter,
primary megaloureter, aperistaltic megaureter, or achalasia
of the ureter.
• In this condition, ureteral dilation occurs above a
short, adynamic, extra vesicle distal ureteral segment.
• The abnormal segment of distal ureter may have
increased collagen between the muscle fibers at this
level or a deficiency in longitudinal muscle.
211
• In adults, the lesion is 2 . 5 times more frequent on the
left. In children, it is four times more frequent in boys,
and bilateral involvement is almost exclusively a male
disease. In all age groups, 20% of cases are bilateral.
• Surgery is considered in patients with infection, stones,
persistent symptoms, or significant hydronephrosis.
Mild cases may be followed radiographically.
RADIOLOGIC
• This abnormal distal ureteral segment is approximately
1 .5 em long and does not transmit a peristaltic wave
when examined fluoroscopically.
• There is a high association with other abnormalities of
the genitourinary system. Uretereopelvic junction
obstruction may be found in 2 5 % of cases. Contralateral
reflux has been reported in 6% to 8% of cases,
contralateral renal agenesis in 4% to 1 5%, contralateral
ureteral duplication in 4% to 6%, a calyceal diverticulum
in 4%, and contralateral ureterocele in 3%.
• Megacalyces, ipsilateral cryptorchidism, and ectopic
ureteroceles have also occurred in association with this
condition .
• SUGGESTED READING
MacKinnon KJ, Foote JW, Wiglesworth FW, Blennerhassett JB. The
pathology of the adynamic distal ureteral segment. J Urol
1970; 103: 1 34-1 37.
McLaughlin AP , Pfister RC, Leadbetter WF, et aI. The pathophysiology
of primary megaloureter. J UroI 1 973;109 :805-8 1 1 .
MeUins HZ. Cystic dilatations of the upper urinary tract: A radiolo·
gist'S developmental model. Radiology 1984; 1 5 3 :29 1-30 1 .

Front 103

A 32-year-old diabetic woman presents with dysuria

Back 103

DIFFERENTIAL DIAGNOSIS
• Enterovesicle fistula: This is most commonly caused
by diverticulitis, inflammatory bowel disease, or colorectal
carcinoma. While intraluminal gas is characteristic,
submucosal gas collections are uncommon.
• Penetrating trauma: In a patient with a history of knife
or gunshot injury, a small amount of pelvic gas is possib
e
'
but it should not create such a large collection.
• Instrumentation: Intraluminal gas may be seen following
cystoscopy, cystography, or Foley catheter
placement. Again, linear submucosal gas would not be
expected.
• Pneumatosis intestinalis: Gas within the wall of small
or large bowel can have a linear appearance; however,
the size and location of this abnormality strongly suggest
bladder pathology.
• Emphysematous cystitis: This diagnosis is most likely
in a diabetic patient with gas in the expected position
of the bladder lumen and wall.
+ DIAGNOSIS: Emphysematous cystitis (cystitis
emphysematosa).
+ KEY FACTS
CLINICAL
• This is an uncommon inflammatory condition of the urinary
bladder, usually with a transient and benign course.
• Gas localizes in the bladder submucosa, and often
within the bladder lumen.
213
• E. coli is the most common causative organism, with
glycosuria, stasis, neurogenic bladder, and chronic urinary
tract infection as predisposing factors.
• The female-to-male ratio is 2 to l .
• Symptoms include frequency, dysuria, and, occasionally,
pneumaturia.
• Treatment consists of antibiotics, control of diabetes,
and relief of obstruction, if present.
RADIOLOGIC
• The plain radiograph is often diagnostic.
• Gas within the submucosa may be linear or have a
cobblestone appearance.
• CT is rarely indicated but elegantly demonstrates gas
witlun the lumen and witlUn a thickened bladder wall.
• Ultrasowld also depicts a thickened bladder wall and
irregular echogenic foci with acoustic shadowing

Front 104

A 72-year-old woman presents with hematuria

Back 104

DIFFERENTIAL DIAGNOSIS
• Pseudoureterocele: The eccentric halo just medial to
the distal left ureterocele indicates there is a left
pseudoureterocele.
• Ureterocele: The postvoid film shows no evidence of a
periureteral abnormality. The mucosa adjacent to the
left ureterocele is not optimally imaged on the
postvoid film and precludes the diagnosis of a
pseudoureterocele. Given the patient's history of
hematuria and what would otherwise appear to be a
negative study, cystoscopy would follow, revealing
bladder pathology adjacent to the distal left ureter.
+ DIAGNOSIS: Left-sided pseudoureterocele secondary
to a transitional cell carcinoma of the bladder.
+ KEY FACTS
CLINICAL
• Ureteroceles are due to a defect in the muscular layer
of the ureter, often with a defect in the bladder wall
itself.
• There are two types of ureteroceles: intravesicle and
ectopic.
• I ntravesicle ureteroceles may be unilateral or bilateral,
and they are more often seen in females than in males.
A "cobra head" defect is seen in the bladder, with a
thin lucent line or halo around the lumen.
215
• Ectopic ureteroceles insert medially and caudally to the
site of the normal ureteral orifice, often extending into
the bladder neck or urethra.
• Pseudoureteroceles are secondary to edema from a
ureteral stone, bullous edema of the bladder, or neoplastic
disease. Neoplasms that can cause this appearance
include transitional cell carcinoma (TCC) of the
bladder or invasion of the bladder by squamous cell
carcinoma of the cervix. Radiation cystitis can also lead
to the appearance of a pseudoureterocele.
RADIOLOGIC
• The cobra head deformity with a thin lucent halo is
the typical finding in a ureterocele. Deformity or thickening
of the surrounding halo is a worrisome finding.
Further work-up should include cystoscopy.
• Pseudoureteroceles are distinguished by asymmetry of
the dilated ureteral lumen, moderate to severe obstruction
of the upper tract, and evidence that this is an
acquired abnormality.
+ SUGGESTED READING
Thornbury JR, Silver TM, Vinson RK. Ureteroceles vs. pseudoureteroceles
in adults. Radiology 1 977; 1 22:81-84.

Front 105

A 60-year-old man presents with left flank pain.

Back 105

Renal cell carcinoma ( RCC): RCC can occasionally
present as an infiltrative central renal mass. The presence
of retroperitoneal lymphadenopathy is consistent
with regional involvement in a patient with a left-sided
RCC, although other causes of primary renal tumor
must also be considered. Typically, RCCs are exophytic,
contour-deforming lesions.
• Transitional cell carcinoma (TCC): TCC originates
from the urothelium of the pelvicaliceal system. There
are many manifestations of TCC, one of which is an
infiltrative renal mass. Regional lymphadenopathy and
vascular invasion are seen less commonly than in
patients with RCC.
• Lymphoma: A solitary infiltrative renal mass is one of
the presentations of renal lymphoma. More common
presentations include multifocal renal masses and infiltration
from bulky retroperitoneal lymphadenopathy.
• Metastasis: A renal metastasis can cause a mass with
this appearance, and the presence of retroperitoneal
lymphadenopathy does not exclude the possibility of a
renal metastasis. It is useful to investigate for a history
or the presence of common primary neoplasms in
patients with this CT appearance, particularly of the
lung, colon, and breast.
+ DIAGNOSIS: Transitional cell carcinoma.
+ KEY FACTS
CLINICAL
• Peak incidence of TCC is in the seventh decade.
• TCC occurs most often in men, with a male-to-female
ratio of 2 to l .
• Presenting symptoms include hematuria, flank. pain,
and either or both dysuria and an abdominal mass.
• The upper urinary tract is the site of 1 0% to 1 5% of
TCCs.
• TCC comprises d O% of malignant renal tumors.
• Renal parenchymal invasion by TCC results in a poor
prognosis.
• Risk factors for TCC of the upper tract:
High-grade bladder TCC
Analgesic abuse
Cigarette smoking
Cyclophosphamide therapy
Radiation exposure
Aniline dye workers
217
Chronic inflammation ( pyelitis cystica/ glandularis)
• TCC may contain coarse punctate calcific deposits in
d O% of cases.
RADIOLOGIC
• The radiologic manifestations of TCC are varied.
• On intravenous urography, TCC may appear as a discrete
filling defect within the renal collecting system, a
filling defect within a distended calyx, caliceal obliteration,
caliceal amputation, hydronephrosis with renal
enlargement, or reduced function without renal
enlargement.
• The surface of a pelvicaliceal filling defect may be
smooth, irregular, or stippled ( the "stipple-sign " ) . An
oncocalyx occurs when transitional cell tumor distends
a calyx .
• A phantom calyx occurs when tumor obstructs a caliceal
infundibulum.
• CT manifestations of TCC mimic their appearance on
intravenous urography. Patterns of disease include caliceal
or renal pelvis filling defect, pelvicaliceal irregularity,
infundibular stenosis, caliceal cut-off, caliceal
expansion, and focal or global nonvisualization.
• Differentiation of TCC from RCC is aided by the
more modest enhancement of a transitional cell lesion
as opposed to the typical hypervascular, nonnecrotic,
and noncystic RCC.
• Transitional cell tumors are typically centrally located,
with either or both centrifugal expansion and invasion
of the kidney.
• There are unusual forms of TCC on CT, including the
hydronephrotic form where an enhancing soft-tissue
mass may be seen at the apex of a dilated renal pelvis
indicative of tumor-causing ureteropelvic junction
obstruction. Nodular thickening of the wall of the
renal pelvis may also occur.

Front 106

A middle-aged woman has a several-month history of chronic flank pain and a palpable
flank mass.

Back 106

Pyonephrosis secondary to an obstructing calculus:
While this may have been a possibility at an earlier
stage, one can no longer discern dilated calyces, and
the kidney appears destroyed by a process more extensive
than one would expect for pyonephrosis.
• Xanthogranulomatous pyelonephritis (XGP): A
poorly or nonfunctioning kidney with an associated
staghorn calculus makes this the most likely diagnosis,
although this requires pathologic confirmation.
• Chronic pyelonephritis secondary to calculus disease:
Since XGP is a pathologic diagnosis, the possibility
exists that this is a nongranulomatous response of
the kidney to chronic obstruction. The spread of disease
into the perirenal space, however, makes XGP a
more likely diagnosis.
• Replacement lipomatosis of the kidney (RLK): This
can be differentiated from XGP by its fibrofatty proliferation.
The attenuation of the tissue replacing the
kidney in this case is near that of water and is not characteristic
of fat, therefore this is not a case of RLK.
+ DIAGNOSIS: Xanthogranulomatous
pyelonephritis.
+ KEY FACTS
CLINICAL
• XGP is a chronic granulomatous inflammation of the
kidney. The parenchyma is replaced by xanthoma cells,
which are lipid-laden macrophages.
• The etiology of XGP is unknown, though it may be
caused by chronic urinary tract obstruction with superimposed
recurrent infection. Diabetes mellitus and primary
hyperparathyroidism may be associated with XGP
in some cases.
• Fever, dysuria, and flank pain in a middle-aged woman
is the classic presentation. Approximately 70% of
patients are women. Tenderness in the renal area and a
palpable abdominal or flank mass is found in approximately
50% of cases.
• Multiorganism urinary tract infections are characteristic.
While Proteus is common, E. coli, Klebsiella,
Pseudomonas) and Enterobacter may also be cultured.
More than 80% of patients have pyuria and proteinuria.
Laboratory studies show elevated erythrocyte
sedimentation rate, anemia, and leukocytosis.
• Reversible hepatic dysfunction has been reported in
association with XGP.
• A staghorn calculus is often found. An acalculous variety
of XGP has been reported.
• Both diffuse and focal (turnefactive) varieties exist. The
diffilse form is more common, occurring in 85% of cases.
• Involvement of the perirenal spaces, psoas muscles,
small bowel, diaphragm, lung, or soft tissues of the
flank may occur.
219
RADIOLOGIC
• The plain radiograph typically demonstrates enlargement
of the infected kidney with evidence of a
staghorn calculus. Extension into the perirenal space or
pararenal space is suggested by indistinct outlines of
tl1e kidney or psoas muscle.
• The intravenous urogram shows non function or faint
opacification of the kidney.
• On ultrasound, the kidney is typically enlarged, with
multiple fluid collections representing dilated calyces
and areas of parenchymal destruction. Irregular masses,
eitl1er anechoic or hypoechoic, with low-level internal
echoes and varying degrees of through-transmission
are frequently seen. Acoustical shadowing of the central
staghorn calculus may be obscured by peri pelvic
fibrosis. Hypoechoic fluid in the perirenal space is secondary
to extension of disease.
• On CT, the kidney is enlarged diffusely, and the renal
parenchyma is replaced by low-attenuation masses.
These masses measure between -20 and + 1 0 H U
depending o n lipid content. True fat density i s not
seen in XGP. Rim enhancement of well-vascularized
granulation tissue may occur. Central calcification is
seen frequently, as well as calyceal calculi or small areas
of calcification in the adjacent parenchyma. The renal
pelvis is contracted. Gerota's fascia may be thickened.
Low-attenuation masses may be present in the
pararenal and perirenal spaces. Less common CT findings
include acalculous XGP, a small contracted kidney
with parenchymal destruction, and massive pelvic dilation
mimicking obstructive hydronephrosis. Focal
( tumefactive) XGP can mimic an RCC. Enhancement
is demonstrated on postcontrast CT. Typically, a calculus
is seen at the apex of the focal mass.
• Approximately 70% of patients have either staghorn
calculi or multiple calyceal stones.
• XGP can extend to involve the perirenal and pararenal
spaces or ipsilateral psoas muscle. Rarely XGP can involve
the diaphragm, the paraspinal muscles, and the skin.

Front 107

A 39-year-old man presents with right flank pain.

Back 107

DIFFERENTIAL DIAGNOSIS
• Pyelonephritis: Patients with this common condition
present with flank pain, fever, nausea, and vomiting.
Imaging studies, including intravenous urography,
ultrasound, and CT, are usually normal, although on
contrast-enhanced CT, parenchymal striations may be
seen. While acute pyelonephritis may cause nephromegaly
and stranding of the perinephric fat, the ureteral
dilation and ureteral calculus argue against tlus
being the primary diagnostic choice.
• Renal lymphoma: Lymphoma involves the kidneys
either by hematogeneous spread or by direct extension
of hilar adenopathy. On CT, renal lymphoma may present
as multiple masses, a solitary mass, or a renal
hilar/retroperitoneal mass directly invading the kidney.
• Ureteral obstruction due to a calculus: The unilateral
nephromegaly, perinephric fluid, pelvicaliureterectasis,
and ureteral calcification all indicate an obstruction
caused by a ureteral calculus.
+ DIAGNOSIS: Acute ureteral obstruction caused
by a calculus.
+ KEY FACTS
CLINICAL
• The most common cause of ureteral obstruction is a
calculus lodged in the ureter.
• Common sites of obstruction include tile ureteropelvic
junction, sites of blood vessels crossing the ureter, the
pelvic brim, and the ureterovesical junction.
• Most small stones <5 mm in diameter will pass
spontaneously.
• Calcium oxylate and calcium oxylate mixed Witll phosphate
are the most common stones.
• Uric acid stones are associated with acidic urine, uricosuric
drugs, and hyperuricemia. These stones are often
221
radiolucent on plain radiographs but are always hyperattenuating
on CT.
RADIOLOGIC
• Intravenous urography is the traditional metllod to
confirm a suspected ureteral obstruction in a patient
with renal colic. Classic findings include delayed
parenchymal enhancement, delayed excretion, and collecting
system dilation to the level of the calculus.
• CT has been shown to be accurate in the work-up of
patients with renal colic. These studies are best performed
using a spiral technique without intravenous or
oral contrast material. Classic findings include
nephromegaly, perinephric stranding, and collecting system
dilation that extends to the level of the calculus.
• Advantages of spiral CT over intravenous urography
include elimination of the need for intravenous contrast
material, the occasional demonstration of nonurinary
causes of flank pain, and a shorter exanlination time.
• Disadvantages of spiral CT include difficulty in differentiating
vascular calcifications and phleboliths from
ureteral stones, inaccurate demonstration of stone size
particularly along tile cranial-caudal axis of stones, and
'
lack of "functional" information in regard to the
degree of obstruction

Front 108

A 67-year-old asymptomatic man has a prostate-specific antigen (PSA) level of 1 2.0
ng/elL (normal < 4.0 ng/elL).

Back 108

DIFFERENTIAL DIAGNOSIS
• Adenocarcinoma of the prostate, postbiopsy hemorrhage,
and focal scar: This appearance has a limited
differential diagnosis. Well-defined, focal, low signal
intensity in the peripheral zone of the prostate gland
on T2-weighted images is usually due to adenocarcinoma,
postbiopsy hemorrhage, or occasionally, a focal
scar. Hemorrhage can be diagnosed when there are
foci of high signal intensity on T l -weighted images.
Diffuse low signal intensity in the peripheral zone on
T2-weighted images may also be seen in cases of prostatitis
or postradiotherapy.
+ DIAGNOSIS: Adenocarcinoma of the prostate
with postbiopsy hemorrhage.
+ KEY FACTS
CLINICAL
• Adenocarcinoma of the prostate is the second leading
cause of cancer death among American men.
• Prostate cancer is most commonly detected by routine
screening, which includes a digital rectal examination
and a serum PSA level.
• Any suspicious findings should lead to a transrectal
ultrasound-guided biopsy which samples all quadrants
of the gland (sextant biopsies) .
• Staging o f prostate carcinoma i s by the WhitmoreJewitt
system, which is as follows: (A) nonpalpable,
confined to prostate; ( B ) palpable, confined to
prostate; ( C ) extracapsular extension; ( D 1 ) regional
nodes; ( D 2 ) distant nodes.
• The 5 -year survival for stage D l is 50%.
223
• The treatment for stage A or B prostate carcinoma
includes a radical prostatectomy or radiotherapy depending
on the age of the patient. The treatment for stages C
or D includes hormone therapy or radiotherapy.
RADIOLOGIC
• Plain films or intravenous urography may demonstrate
osteoblastic metastases, particularly in the bony pelvis.
• With ultrasound, most prostate cancers are hypoechoic,
but only about 20% of hypoechoic lesions
noted are malignant. The larger the lesion, the more
likely it is to be malignant.
• On CT, prostate carcinoma may be seen as a lowattenuation
lesion in the peripheral zone; however, tlus
is not the imaging modality of choice.
• On M RI , prostate carcinoma is of low signal intensity
on both T l - and T2-weighted images. The presence of
postbiopsy hemorrhage is seen as a focus of high signal
intensity on the T l -weighted image. MRI is much
more useful for staging prostate carcinoma than for
screening.

Front 109

A 75-year-old asymptomatic woman with a history of colon cancer.

Back 109

DIFFERENTIAL DIAGNOSIS
• Metastasis: This diagnosis is unlikely because the mass
has a high lipid content, as evidenced by the loss of
signal intensity on the opposed phase image. The T2
value would likely be >60 ms in metastases.
• Pheochromocytoma: A much higher signal intensity on
the T2-weighted image and, therefore, a longer calculated
T2 value would be expected in this diagnosis.
• Nonhyperfunctioning adenoma: This is the most
likely diagnosis given the size and loss of signal intensity
on the opposed-phase images, even though the
patient has a known malignancy.
+ DIAGNOSIS: Nonhyperfunctioning adenoma.
+ KEY FACTS
CLINICAL
• Adrenocortical adenomas may be nonhyperfunctioning
or hyperfunctioning. The incidence of nonhyperfunctioning
adcnomas in the general population is 1 % to
3%.
• Hyperfimctioning adenomas may secrete:
Cortisol; Cushing's syndrome ( adenoma are usually
>-4 cm in diameter)
225
Aldosterone: Conn's syndrome ( adenomas are usually
<2 cm in dianleter)
Androgens: virilization
RADIOLOGIC
• On CT, a precontrast attenuation value <0 Hounsfield
units ( H U ) signifies a benign condition; a precontrast
attenuation value + 1 - 1 0 HU signifies that the adenoma
is likely benign and may warrant follow-up based
on the clinical setting.
• Opposed-phase MRI results in lower signal of the
lesion compared with conventional in-phase M RI due
to intracytoplasmic lipid. Calculated T2 values are generally
<60 ms.
• Malignant imaging features include large size ( > 5 cm),
heterogeneity, intense contrast enhancement, and an
increase i n size on follow-up imaging.
• Imaging studies cannot differentiate hyperfunctioning
from nonhyperfunctioning adenomas.
+ SUGGESTED READING
McLoughJin RF, Bilbey TH. Tumors of the adrenal gland: Findings
on CT and MR imaging. AJR Am J Roentgenol 1994 ; 1 63:
1 4 1 3- 1 4 1 8 .
Ros PR, Bidgood WD. Abdominal Magnetic Resonance Imaging.
St. Louis: Mosby, 1993 ;348-362.

Front 110

A 67-year-old woman presents with vaginal bleeding

Back 110

Endometrial carcinoma with extension to the uterine
cervix: This should be the primary consideration
in this postmenopausal patient.
• Endometrial polyp: This is a possibility; however,
polyps typically appear more focal and round. Only
when it is surrounded by endometrial fluid can one
make the definitive diagnosis of a polyp.
• Endometrial hyperplasia: This entity can be impossible
to differentiate from endometrial carcinoma when
the disease process is confined to the uterus. However,
the disease process in this case clearly extends into the
cervix, making endometrial hyperplasia very unlikely.
• Retained placenta with hemorrhage or pus: These
processes tend to be more heterogeneous and, of
course, would not be supported by the history.
• Invasive molar pregnancy: This would also be a consideration
in a patient with the appropriate history and
elevated human chorionic gonadotropin values.
+ DIAGNOSIS: Endometrial carcinoma with invasion
of the myometrium and cervix, FIGO stage II.
+ KEY FACTS
CLINICAL
• Although 80% of cases of endometrial carcinoma occur
in postmenopausal women, 90% of postmenopausal
bleeding is caused by benign disease.
• Endometrial carcinoma is staged as follows according
to the FIGO system:
Stage
I
IA
Description
Confined to the uterine corpus
Confined to the endometrium
I E Invasion confined t o the inner 5 0 % o f the
myometrium
IC Invasion extends into the outer 50% of the
myometrium
II Extension to the uterine cervix
I I I Extrauterine spread limited to the true pelvis
IVA Extension to the bladder or rectum
!VB Distant metastases
• The incidence of pelvic lymph node involvement
increases dramatically with stage IC and II lesions.
• Endometrial carcinoma can be either focal or diffuse.
The current case is a good example of diffuse disease.
RADIOLOGIC
• Ultrasound is somewhat limited in its ability to distinguish
between endometrial carcinoma and other causes
of endometrial thickening.
• The accepted range of normal for endometrial thickness,
as determined by adding the measurements of the
227
anterior and posterior components of the endometrium,
depends on the hormonal status of the patient, as
follows:
Hormonal status
Premenopausal
Proliferative phase
Secretory phase
Postmenopausal
Without estrogen replacement
With estrogen replacement
Normal range
4 to 8 mm
7 to 1 4 mm
4 to 8 mm
< 1 0 mm
• In two studies of patients with postmenopausal bleeding,
no patient with an endometrial thickness of <5
mm had malignant pathology.
• On sagittal T2 -weighted M R images, the junctional
zone will clearly separate the endometrium from the
myometrium in most patients. Disruption of the junctional
zone is evidence for invasion into the myometrium.
However, approximately 50% of postmenopausal
women will not have a visible junctional zone on T2-
weighted images. The use of gadolinium-enhanced
dynamic imaging produces improved contrast between
the enhancing endometrial carcinoma and the even
more strongly enhancing myometrium. Because
endometrial carcinoma enhances more than normal
endometrium, superficial lesions are more easily recognized
after enhancement. The junctional zone can also
be delineated better using this technique.
• The accuracy of endovaginal ultrasound and MRI,
using T2 -weighted imaging, in the determination of
the depth of myometrial invasion is approx.imately
76%. The recent use of contrast-enhanced dynamic
MRI of the uterus has increased the accuracy to
approximately 90% in the best hands.

Front 111

A I O-year-old boy with acute onset of right hip pain, fever, and a stiff ankle.

Back 111

Iliopsoas bursitis ( IPB): The location of the mass
anterior to the hip joint, lateral to the femoral vessels,
and deep to the psoas tendon, the teardrop or round
configuration, and its fluid signal intensity characteristics
are in favor of this diagnosis. The associated effusion
indicates communication of the bursa with the hip
joint. The cystic nature can be depicted further with
T1 -weighted gadolinium-enhanced MRI. The wall of
the inflamed bursa would be expected to enhance uniformly
without nodularity, while the fluid will not
enhance. Other studies documented a seronegative
arthropathy.
• Neoplasm: Most tumors have a heterogeneous signal
intensity pattern. T1 -weighted gadolinium-enhanced
MRI helps differentiate tumors like intramuscular myxoma,
synovial sarcoma, and hemangioma, which can
imitate bursitis.
• Femoral hernia: Lack of gas and the signal characteristics
indicating fluid in this mass exclude this condition.
• Abscess: Intramuscular abscess can be excluded because
the collection of fluid is not intramuscular. However, in
general, septic bursitis cannot be excluded unless noninfected
fluid is obtained by percutaneous aspiration.
• Femoral artery aneurysm: Normal femoral vessels are
seen in this patient. Furthermore, the location, fluid
nature, age of the patient, and the communication
with joint space are not consistent with this diagnosis.
+ DIAGNOSIS: Iliopsoas bursitis associated with
seronegative spondyloartbropathy.
+ KEY FACTS
CLINICAL
• The iliopsoas bursa is the largest bursa in the body and
is present in 98% of adults, interposed between the ilIacus
muscle/psoas tendon and the anterior capsule of
the hip, lateral to the femoral artery, vein, and nerve.
Communication exists between the iliopsoas bursa and
the hip joint in 1 4% of adults.
• Inflammation and enlargement of the iliopsoas bursa
may occur secondary to hip joint disease or, occasionally,
as a primary bursal process.
• Diseases associated with IPB include seropositive and
seronegative arthropathies, osteoarthritis, pigmented villonodular
synovitis, synovial chondromatosis, infection,
hip prosthesis, occupational trauma, and sports injuries.
• Clinical presentation in IPB includes pain, mass lesion,
and compression syndromes of the inguinal compartment
(pseudothrombophlebitis, femoral nerve neuropathy
that may simulate L4 radiculopathy) .
Retroperitoneal extension o f the iliopsoas bursa may
present as a palpable abdominal or pelvic mass.
• IPB is frequently confused with a femoral hernia,
lymphadenopathy, neoplasms, or a femoral artery
aneurysm.
231
• Therapy for IPB is variable. Rest and nonsteroidal antiinflammatory
drugs are indicated for mild cases.
Aspiration and corticosteroid injection may be
required in more severe cases. Occasionally, surgical
resection of the bursa is necessary.
RADIOLOGIC
• Early, accurate diagnosis of IPB is facilitated by appropriate
radiologic studies.
• Conventional radiographs can help assess underlying
hip joint disorders such as osteoarthritis or rheumatoid
arthritis.
• Ultrasound may demonstrate the fluid-filled nature of
palpable lesions and can guide needle aspiration .
• Contrast bursography outlines the extent of bursal
enlargement.
• Hip arthrography is definitive in establishing the diagnosis
when a communication exists.
• On CT, a water attenuation mass is typically seen in
close apposition to the tendon muscle at the level of the
hip joint and lateral to the femoral vessels. When a communication
exists, an associated hip effusion may be
seen. If the bursitis is secondary to a hip arthropathy,
evidence of osteoarthritis or rheumatoid arthritis may be
seen. Intravenous contrast material enhances the wall of
the bursa but not the contents, as expected for a fluid
collection in an inflamed bursa. In primary IPB, the hip
joint may be normal. If there is no communication with
the joint, there will be no evidence of a hip effusion.
• The soft-tissue contrast, noninvasiveness, and multiplanar
capability of MRI make it superior for assessing IPB.
Underlying arthropathic changes can be characterized in
a case of secondary IPB. The signal intensity of uncomplica
ted bursitis is tllat of fluid. Debris, loose bodies, or
blood yield different signal intensities. Contrast enhancement
of the inflamed wall due to hypervascularity is typically
seen. Signal intensity in synovial chondromatosis of
the iliopsoas bursa varies depending on the degree of calcification
of the cartilaginous nodules. However, in pigmented
villonodular IPB, the hemosiderin will typically
be of low signal intensity on all sequences.
• MRI will make the positive diagnosis of IPB in most
clinical situations and exclude other conditions such as
a hernia, tumor, lymph node, hematoma, aneurysm,
and abscess. Ultrasowld or CT-guided bursal aspiration
can exclude septic bursitis, detect the presence of
crystals, and provide a means of drainage of the bursa
and injection of corticosteroids.

Front 112

A 35-year-old woman who fell and twisted her ankle while running downstairs.
FIGURE 5-2A Anteroposterior radiograph of the ankle. This view
gives the false impression of a non displaced spiral fracture of the distal
fibula and widened medial joint space.
FIGURE 5-2B Lateral radiograph of the ankle. Fracture displacement
is more

Back 112

DIFFERENTIAL DIAGNOSIS
• Pronation-abduction injury: This is an uncommon
fracture pattern characterized by a low, oblique fibular
fracture at the level of the ankle joint.
• Supination-external rotation ( SER) injury: These
injuries are characterized by a long oblique fracture of
the distal fibula usually measuring 2 to 4 cm in length.
ot uncommonly, the fracture is most apparent on the
lateral view of the ankle.
• Supination-adduction injury: This injury causes a
horizontally oriented fracture in the distal fibula, usually
below the joint line.
• Pronation-external rotation injury: This injury produces
a relatively horizontal fracture of the fibular diaphysis
approximately 5 to 8 cm above the ankle joint.
+ DIAGNOSIS: Supination-external rotation injury_
+ KEY FACTS
CLINICAL
• SER is the most commonly observed ankle fracture
pattern .
• The fracture is preceded by ankle inversion and rupture
of the anterior tibiofibular ligament.
• Asymmetric widening of the ankle mortise denotes
instability, an indication for open reduction with internal
fixation.
RADIOLOGIC
• There is typically a long (2 to 4 cm), oblique-spiral
fracture of the distal fibula.
• The fracture is often seen best on the lateral view.
233
• SER injury may be associated with either or both posterior
and medial malleolus fractures or a tear of the
deltoid ligament.
• The patterns of ankle fractures described in the differential
diagnosis are derived from the Lauge-Hansen
classification system. Although other classification
schemes exist, it is the most widely used for communicating
radiographic findings, determining appropriate
orthopedic therapy, and predicting the prognosis.
• The importance of the classification system is the
recognition that ankle fractures are not randomly oriented
fractures through the medial, lateral, and posterior
malleoli, but rather occur in a stereotypical and
predictable manner based on the mechanism of injury,
the position of the foot and ankle at the time of injury,
and the relative strength and weakness of the bony and
ligamentous structures about the ankle.
• The four types of fractures cause a relatively unique pattern
of injury to the fibula, which is so characteristic it
allows one to easily classify the four fracture types.
+ SUGGESTED READING
Berquist TH. I maging of Orthopedic Trauma. New York: Raven,
1 992;5 1 2-5 1 7 .

Front 113

A 33-year-old woman with diffuse bone pain and a chronic disease

Back 113

DIFFERENTIAL DIAGNOSIS
• Osteopetrosis: Diffuse sclerosis results in a bonewithin-
bone appearance or a sandwich vertebra appearance.
Anterior vascular notches may be seen in the
vertebral bodies, but lytic lesions do not occur.
• Systemic mastocytosis: Osteosclerosis may be diffuse
or patchy and multi focal . Multiple lytic lesions
can also occur, which are usually surrounded by a
halo of sclerosis.
• Renal osteodystrophy and secondary hyperparathyroidism:
Osteosclerosis manifests as a rugger-jersey
spine appearance. Subliganlentous bone resorption
simulating erosions and lytic brown tumors are adclitional
features. This is the most likely cliagnosis.
• Myelofibrosis: A diffuse increase in bone density is
most commonly seen, but small areas of relative radiolucency
or lytic lesions can also be present.
+ DIAGNOSIS: Renal osteodystrophy and secondary
hyperparathyroidism.
+ KEY FACTS
CLINICAL
• Musculoskeletal manifestations of chronic renal insufficiency
are increasingly common due to prolonged survival
with hemodialysis.
235
• Symptomatic bone disease may consist of pain, tenderness,
swelling, and deformity.
• The most common cause of chronic renal insufficiency
is glomerulonephritis.
• Hyperphosphatemia results in hyperplasia of the
parathyroid gland chief cells and increased levels of
parathyroid hormone.
RADIOLOGIC
• Osteosclerosis most commonly involves the cancellous
bone of the spine, but it may also involve the pelvis,
ribs, clavicle, and the ends of long bones.
• Bone resorption occurs in subperiosteal, subchondral,
subligamentous, and endosteal locations.
• Brown tumors or osteoclastomas are well-defined lytic
lesions that may heal with sclerosis after treatment of
the hyperparathyroiclism.
+ SUGGESTED READING
Murphey MD, Sartoris DJ, Quale JL, et aI. Musculoskeletal manifestations
of chronic renal insufficiency. Radiographics
1993; 1 3 : 357-379.
Resnick D. Bone and Joint I maging. Philadelph.ia: Saunders,
1989;630-646.

Front 114

An 86-year-old woman with arthralgia of the knees, hips, and wrists with periodic
exacerbations. She has recently complained of increasing right hip pain

Back 114

DIFFERENTIAL DIAGNOSIS
• Calcium pyrophosphate deposition disease ( CPPD):
This diagnosis is favored given the distribution of the
process and the presence of chondrocalcinosis of fibrocartilaginous
and hyaline cartilaginous structures. Also
supporting this diagnosis is the prominent subchondral
cyst formation in the right femoral head.
• Osteoarthritis: Many of the features noted on these
films are consistent with osteoarthritis, but the presence
of chondrocalcinosis is in keeping with the diagnosis
of CPPD. Some of the findings, such as the
degenerative changes in the distal intraphalangeal
joints, could represent osteoarthritis, but the arthritis
of CPPD can have features identical to osteoarthritis
or the degenerative process may be accelerated by
CPPD .
• Erosive (inflammatory) osteoarthritis: Central
depressions of the articular surfaces of the distal phalanges
of the left second, fourth, and fifth digits and
right fourth digit are seen in the case shown . This
appearance, which gives a gull-wing appearance at the
left fifth distant phalanx, can be seen with the central
erosions of erosive osteoarthritis. Relatively mild deformities,
as noted in this case, can be seen in osteoarthritis
or with degenerative type changes associated with
CPPD .
• Osteonecrosis: The area of lucency with adjacent sclerosis
in the right femoral head with associated articular
collapse makes osteonecrosis a consideration, but collapse
can occur secondary to structural weakening
associated with subchondral cyst formation. In addition,
a fair amount of acetabular proliferative change is
seen, and the joint space narrowing is most pronounced
superomedially.
• DIAGNOSIS: Calcium pyrophosphate deposition
disease.
KEY FACTS
CLINICAL
237
• CPPD mainly affects middle-aged and elderly subjects.
• CPPD is clinically similar to osteoarthritis but has a
greater tendency for acute exacerbations of the disease.
• Pseudogout occurs in approximately 1 0% to 20% of
cases.
• Conditions that are strongly associated with CPPD
include primary hyperparathyroidism, hemochromatosis,
and, to a lesser extent, gout.
RADIOLOGIC
• The features of CPPD are similar to osteoarthritis, but
CPPD has a greater tendency for subchondral cyst formation,
destructive changes of the osteochondral articular
surfaces, and joint effusion.
• Osteophyte formation is variable.
• Soft-tissue calcifications typically involve fibrocartilages
(such as the menisci of the knee, triangular fibrocartilage,
acetabular labrum, symphysis pubis, or annulus
fibrosis ) and the hyaline cartilage ( particularly in the
wrist, knees, elbows, and hips) . Other periarticular soft
tissues may also be involved.
• The distribution of CPPD includes areas less typical
for osteoarthritis, such as the radiocarpal joints,
elbows, or glenohumeral joints. There may be isolated
or accelerated abnormalities at the metatarsophalangeal
joints, patellofemoral joints, or talonavicular joints

Front 115

A 34-year-old man with tenderness along the medial joint line of the right knee.

Back 115

DIFFERENTIAL DIAGNOSIS
• Popliteal cyst: These cysts tend to be located more
posteriorly and not as meclially as in this case. The
neck of a popliteal cyst typically protrudes through the
space between the meclial head of the gastrocnemius
and the semimembranosus muscles, not through the
meclial joint capsule as in this case.
• Ganglion cyst: The signal intensity of the loculated
collection is consistent with a fluid-filled/jelly-like viscous
substance. The presence of an associated meniscal
tear makes this cliagnosis less likely.
• Meniscal cyst: A horizontal meniscal tear with an
associated cyst is characteristic of this cliagnosis.
• Pes anserinus bursitis: Either or both fluid and
edema are often seen in association with inflammation
of the pes anserine, namely, the semitendinosis, sartorius,
and gracilis muscles.
+ DIAGNOSIS: Meniscal cyst.
+ KEY FACTS
CLINICAL
• Meniscal cysts contain jelly-like mucinous or synovial
fluid. The neck of the meniscal cyst is often traced to
the joint line.
• Meniscal cysts are thought to occur more commonly
on the lateral side of the knee rather than the meclial
239
side, although Burk et al. found more meclial meniscal
cysts in their series.
• For ganglion cysts, excision of the lesion is sufficient.
However, if a meniscal cyst is excised in a similar
fashion, it will typically recur. As such, the cliagnosis
of a meniscal cyst in this situation requires treatment
of the underlying meniscal abnormality to prevent
recurrence.
• It has been suggested that cysts located posteriorly to
the medial collateral ligament are more apt to penetrate
the capsule and to expand in an unrestricted fashion.
These cysts may be miscliagnosed as ganglion cysts
or popliteal cysts.
RADIOLOGIC
• On T2-weighted MRl, a loculated fluid collection
extencling from the joint line is seen.
• On proton density or T l -weighted MRI, the tear of
the underlying meniscus is identified. These tears are
typically horizontal, with the defect extencling to the
meniscocapsular junction rather than to the superior or
inferior articular surface .

Front 116

Patient A: a 35-year-old man who fell from a ladder onto an outstretched hand and
now complains of shoulder pain. Patient B : a 45-year-old woman who complains of
severe shoulder pain following a grand mal seizure.

Back 116

DIFFERENTIAL DIAGNOSIS
• Anterior dislocation of the shoulder: Anterior shoulder
dislocations characteristically cause anteroinferior
displacement of the humeral head relative to the glenoid.
This position of the humeral head is never seen
in patients with posterior dislocation. In addition,
anterior dislocation leads to total obscuration of the
normal glenohumeral joint space due to overlap of the
humeral head and the glenoid.
• Posterior dislocation of the shoulder: Posterior dislocations
are rare but are characteristic in patients with
seizures, electrical injury, and, occasionally, blunt injury
to the anterior aspect of the shoulder. In virtually all
cases of posterior dislocation, the humeral head and
glenoid remain in the sanle transverse plane, unlike
anterior dislocation, where the humeral head displaces
inferomedially. Some posterior dislocations give the
appearance of a widened glenohumeral joint space,
caused by "perching" of the humeral head on the posterior
labrum. As a result, the distance between the
humeral head and the anterior labrum is widened,
which gives the false impression of a widened joint
space. This feature is never seen in anterior dislocation.
• Pseudodislocation of the shoulder: This term applies
to a clinical presentation in which physical findings
suggest an abnormal position of the humeral head
consistent with a shoulder dislocation. Subsequent
radiographs fail to show a dislocation but do demonstrate
inferior subluxation of the humeral head relative
to the glenoid. Pseudodislocation can be seen in the
setting of brachial plexus injury, chronic shoulder joint
instability, hemarthrosis, and, occasionally, pyarthrosis.
+ DIAGNOSIS: Posterior dislocation of the shoulder.
+ KEY FACTS
CLINICAL
• Less than 3% of all shoulder dislocations are posterior.
• The characteristic setting for this injury is in a patient
after a seizure.
RADIOLOGIC
• "Fixed" internal rotation should immediately raise the
possibility of posterior dislocation of the shoulder.
241
• A "positive" rim sign is present when the distance
between the anterior glenoid rim and the humerus is
..6 mm.
• A post-traumatic "dent" in the anterior aspect of the
articular segment is called the "trough sign. "
• Posterior dislocation remains a challenging diagnosis
when the axillary or "Y" views are unavailable. Such
would be the case on portable chest radiographs
obtained for patients with blunt trauma, electrical
injury, or seizure disorders. Under these circumstances,
it is important to recognize the clues of posterior dislocation
on an anteroposterior view alone. The radiologist
must recognize fixed internal rotation, widening
of the joint space (rim sign) , and loss of the overlap
appearance (half moon) of the normal shoulder joint
as characteristic findings of posterior dislocation on a
frontal film.
• A post-traumatic dent in the humeral head (trough
sign) is a helpful sign but is not always present. Posterior
dislocations can also be seen in conjunction with comminuted
fracture-dislocations of the proxinlal humerus.
In any event, the reader should keep in mind that posterior
dislocations when missed can easily escape clinical
detection and become chronic dislocations. It is not
unusual for patients with chronic posterior dislocation
to remain undiagnosed for months at a time. The radiologist
must always have a high index for a "missed"
posterior dislocation when reviewing outpatient radiographs
in patients with chronic shoulder pain.
• A clinical history of any or all of the following symptoms-
a frozen shoulder, limited range of motion, and
old trauma-should motivate the radiologist to obtain
a dislocation view (axillary view preferred) to exclude
the possibility of a chronic posterior dislocation.

Front 117

A 29-year-old man who presents with left heel pain as well as pain and swelling of
multiple fmgers. On physical examination, there is redness and scaling of the skin
in the right groin.

Back 117

DIFFERENTIAL DIAGNOSIS
• Reiter's syndrome: Calcaneal erosions with proliferative
changes at the plantar fascia insertion site in a
male patient make Reiter's syndrome an important
consideration. The arthritis of Reiter's syndrome, however,
more typically involves the lower extremities. Skin
abnormalities that may be encountered include keratoderma
blennorrhagica (reddened palms and soles) and
balanitis (penile rash ) .
• Ankylosing spondylitis: This diagnosis i s unlikely
given the extent of inflammatory arthritis of the
peripheral appendicular skeleton and no history of
sacroiliitis, spine disease, or hip or shoulder disease.
• Rheumatoid arthritis: The extensive and predominant
distal interphalangeal ( D I P ) involvement, reactive
proliferative changes, and preservation of bone density
are all atypical for rheumatoid arthritis, making this
diagnosis unlikely.
• Psoriatic arthritis: This is the favored diagnosis given
the predominant involvement of DIP joints, presence
of erosions with reactive proliferative bone formation,
the preservation of bone mineral density, and findings
of pencil-in-cup deformity and telescoping of the
fourth digit. The skin changes are also consistent with
psoriatic disease.
• Septic arthritis: This disorder is unlikely because it
most commonly involves a single joint. Septic arthritis,
however, can occur secondarily in a joint affected by a
noninfectious inflammatory arthritis.
+DIAGNOSIS: Psoriatic arthritis.
+ KEY FACTS
CLINICAL
• The arthritis usually is diagnosed after the skin condition
develops. Typical skin findings include a scaly,
micaceous rash involving extensor surfaces.
• Nail abnormalities such as pitting are common in
patients with psoriatic arthritis.
• Of patients with psoriatic arthritis, 2 5 % to 60% are
HLA-B27 positive .
RADIOLOGIC
243
• The hands are the most common target site, with many
cases showing predominant involvement of DIP joints.
• Erosions typically have proliferative change associated
with them, which may give a "Mickey Mouse ears"
appearance or a shaggy, frayed, irregular border to
the erosions.
• Bone density is typically preserved.
• Acro-osteolysis may occur.
• Classic deformities include pencil-in-cup deformity and
telescoping of digits. Subluxations, dislocations, swan
neck deformities, or boutonniere deformities may also
occur.
• Aggressive central erosions may result in joint space
widening.
• The axial skeleton may be involved, with bilateral symmetrical
or bilateral asymmetrical sacroiliitis and nonmarginal
asymmetric syndesmophyte formation at the
discovertebral joints of the spine.
SUGGESTED READING
Brower AC. Arthritis in Black and White. Philadelphia: Saunders,
1 988;1 67-1 84.
Resnick D, Niwayama G. Diagnosis of Bone and Joint Disorders
(2nd ed). Philadelphja: Saunders, 1988; 1 1 7 1-1 1 9 8 .

Front 118

A 2 1 -year-old man who was a restrained passenger in a head-on collision with
another vehicle.

Back 118

DIFFERENTIAL DIAGNOSIS
• Simple compression: Minor compression fra ctures
of the vertebral column are common but do not
usually disrupt the middle or posterior columns of
stability. Usually the degree of compression is <25%
of the vertebral body height, and there is no evidence
of retropulsion or extension of the fr acture
into the posterior elements.
• Burst fr acture: Burst fra ctures are caused by an axial
load on the vertebral column as would occur during a
fa ll fr om a significant height. CT examination would
demonstrate radial dispersion of the vertebral body
fr agments with retropulsion into the spinal canal.
• Chance fr acture: The chance fra cture is produced by a
flexion- distraction mechanism. Fracture lines are typically
seen extending into the posterior elements of the
vertebrae on a lateral view. Characteristically, subde
bilateral pedicle fractures can be seen on the AP view
and should be sought. Chance fra ctures sometimes
produce only minimal anterior compression and can be
confused with simple compression fractures when the
pedicle and posterior element extension of the fr acture
are not appreciated.
+ DIAGNOSIS: Chance fracture .
+ KEY FA CTS
CLINICAL
• Chance fr actures are flexion-distraction injuries of the
thoracolumbar region.
• They are associated with seatbelt/lapbelt restraint.
• There is a high association with intra-abdominal injuries.
RADIOLOGIC
• Chance fr actures can be difficult to diagnose when
undue emphasis is placed on the lateral view of the
245
spine. The degree of vertebral compression may be
slight, giving the fa lse impression of a simple compression
fracture. Regardless of the site of trauma, it is
imperative to give equal time to d1e inspection of the
AP view and lateral views in spine trauma. This is particularly
true fo r chance fractures in which the posterior
element component is often quite impressive on
the AP view while unappreciated on the lateral view.
• Despite the substantial posterior element injury seen in
chance fr actures, neurologic deficits are less common
than with other serious lumbar injuries such as burst
fr actures or fr acture-dislocations of the spine.
• Simple compression fractures of the spine are common,
and ald10ugh they produce severe back pain, they do
not cause neurologic injury. Simple compression fractures
with <25% loss in vertical body height can be
treated conservatively; additional imaging is not needed.
• Compression fractures >25% can be deceptive on radiographs,
and CT can be helpful in excluding retropulsion
of fragments, a finding that is commonly
underestimated fr om plain film analysis.
• Burst fr actures, regardless of their location in the
spine, imply an axial load with radial dispersion of fracture
fra gments. An increase in the interpediculate distance
on the frontal film is a key finding. This further
emphasizes the importance of viewing the anteroposterior
view in spinal trauma. CT and sometimes MRI are
used in the evaluation of burst injuries due to the high
propensity fo r spinal canal compromise .
+ SUGGESTED READING
Berquist TH. Imaging of Orthopedic Trau ma. New York: Rave n,
1992;169-194.
Harris JH, Harris WH, Novelline RA. The Radiology of Emergency
Medicine. Baltimore: Williams & Wilkins, 1993;247-280.

Front 119

A 3-year-old boy with pain and a flrm mass at the upper part of his left knee

Back 119

DIFFERENTIAL DIAGNOSIS
• Ewing's sarcoma: In favor of this possibility is the
presence of a soft-tissue mass, the multilayer or onionskin
periosteal reaction, and the fact that there is sclerosis,
which is related to reactive bone formation.
Ewing's sarcoma, however, more typically produces a
longer diaphyseal lesion. It is excluded in this case by
the presence of cumulus cloud-like malignant osteoid
tumor bone mineralization in the soft tissues.
• Central osteogenic sarcoma: The location of this
lesion, aggressive bone destruction, soft-tissue mass
formation, and cumulus cloud-like mineralization both
within the bone and in the soft-tissue mass overwhelmingly
favor this diagnosis even though the
patient is relatively young.
• Osteomyelitis: Osteomyelitis is typically metaphyseal
and can cause bone destruction, reactive bone formation
in the region of trabecular bone, and periosteal
reaction that can be multilayered. However, this diagnosis
is excluded because of the presence of a softtissue
mass with malignant osteoid type mineralization
and because infection would tend to make fascial
planes indistinct rather than simply displace them.
DIAGNOSIS: Central osteogenic sarcoma of the
distal femur.
KEY FACTS
CLINICAL
• This is the most common primary malignant tumor of
bone in childhood.
• The patients are between 1 5 and 25 years of age in
about 75% of cases.
247
• Approximately 70% of cases occur in long bones, and
approximately 5 5 % occur about the region of the knee.
RADIOLOGIC
• These tumors are typically eccentric in location and
metaphyseal .
• Radiologic features include permeative bone destruction
with cortical disruption and soft-tissue mass formation.
• Periosteal reaction is uncommonly present, having a
"sunburst," "onion peel," "onion skin," or Codman's
triangle appearance.
• Tumor bone formation has a cloud-like appearance,
typically involving the tumor within the bone and
within the soft tissue mass.
• MRI is the modality of choice for staging

Front 120

A 58-year-old man with insulin-dependent diabetes mellitus presents with a severalweek
history of fever and an enlarging mass on the posterior aspect of his right arm

Back 120

Pyomyositis (PM): In the case shown, the intramuscular
cavitation that is hyperintense on T2 -weighted
image, has rim enhancement on Tl -weighted postgadolinium
images, and is associated with edema of
adjacent tissues is consistent with the diagnosis of PM.
• Neoplasm: Tumors and PM both present clinically as
a mass. Malignant tumors may have central necrosis
that could be confused with PM . Sarcomas are limited
to a compartment and are not associated with cellulitis
unless they have been treated with radiation or a
biopsy has been performed. PM is a diffuse process
that extends beyond the compartments involving the
subcutaneous fat and the skin. Soft-tissue lymphomatous
masses may be diffuse and involve the subcutaneous
fat, but they do not cavitate like PM.
• Hematoma: In most instances, there is a clear history
of trauma, and blood components are seen (not present
in this case ) . Central cavitation with rim enhancement
is not a feature of traumatic lesions.
• Myonecrosis: This is a very rare complication of diabetes
mellitus secondary to small vessel disease. Rim
enhancement is not a feature of this condition .
• Myositis: There are numerous conditions associated
with myositis, particularly the connective tissue diseases.
These conditions produce multiple lesions that
do not cavitate, making this an incorrect diagnosis.
+ DIAGNOSIS: Pyomyositis.
+ KEY FACTS
CLINICAL
• PM is a primary bacterial infection involving skeletal
muscles. It is also known as tropical PM because it is
endemic to warm climates. However, incidence of PM
is increasing in temperate countries as well.
• PM tends to occur in the large muscles of the lower
extremities.
• It is caused by Staphylococcus aureus in 90% of cases.
• Contributing factors include trauma, diabetes mellitus,
human immunodeficiency virus ( HIV) infection,
chronic steroid use, connective tissue disorders, history
of malignancy, and various hematologic disorders.
249
• PM has a predictable clinical course that consists of
four stages. Stage 1 has a characteristic insidious onset
with diffuse pain and swelling. In stage 2, there is progressive
pain and enlargement of the extremity. Stage 3
denotes suppuration, and stage 4, resolution. Alternatively,
progression to shock and death occurs in 2%
of patients.
• Most PM cases are treated with surgical drainage and
appropriate intravenous antibiotics.
RADIOLOGIC
• Plain radiographs are nondiagnostic in most instances.
On occasion, they may show an associated osteomyelitis.
• On nuclear scintigraphy, the blood pool phase may
demonstrate nonspecific muscular uptake . Late images
demonstrate osseous uptake in cases with osteomyelitis.
• Ultrasound may detect and localize the process and
demonstrate the presence of cavitation.
• Contrast-enhanced CT defines the abscess wall by the
presence of rim enhancement. PM very often is associated
with cellulitis, which on CT is seen as skin thickening,
stranding of subcutaneous fat, blurring of
intramuscular fat and fascial planes, and distention of
subcutaneous veins

Front 121

A 14-year-old boy with left hip pain. He has no history of trauma.

Back 121

the metaphysis. Extensive bone destruction and the
presence of marrow and muscle edema are uncommon
in this subacute infection.
• Eosinophilic granuloma: These lesions are most
often metaphyseal and multifocal with less marrow
and muscle edema.
• Aneurysmal bone cyst (ABC): The expansile radiograph.ic
appearance favors this diagnosis but would
not account for the marrow and muscle edema.
• Chondroblastoma: This is essentially the only tumor
to involve the greater trochanter, and may have an
aneurysmatic component with edema of adjacent muscle
and marrow. The radiograph.ic and MRI features
and the patient's age are most consistent with a chondroblastoma
and a secondary ABC.
• Clear cell chondrosarcoma: These tumors mimic
chondroblastomas and are usually found in older
patients. They most often involve the femoral head
and are not typically aneurysmal.
DIAGNOSIS: Chondroblastoma of the greater
trochanteric apophysis with secondary aneurysmal
bone cyst.
KEY FACTS
CLINICAL
• Chondroblastoma is a benign cartilaginous tumor
comprising < l % of all primary bone tumors.
• Its incidence is intermediate among other benign cartilaginous
tumors; it is more common than chondromyxoid
fibroma but rarer than enchondroma or
osteochondroma.
• The second decade of life is the most common age of
presentation ( 70%). The male-to-female ratio is 3 to l .
• Symptoms are nonspecific and include pain referred to
the joint adjacent to the lesion.
251
• Curettage and bone grafting is the treatment of choice.
• Local recurrence can occur following surgery. However,
malignant transformation is rare .
RADIOLOGIC
• Chondroblastoma is a geographic lucent lesion with
thin sclerotic margins arising eccentrically in an epiphysis
or apophysis, with or without extension into the
metaphysis.
• The most common sites of involvement, in descending
order, are the epiphyses of the distal femur, proximal
tibia, proximal humerus, and apophysis of the greater
trocanter. Occurrence in the greater trochanter is three
times more common than in the femoral head.
• Detectable punctate calcified chondroid matrix is
found in 60% of patients.
• Up to 60% of patients have benign-appearing periosteal
reaction away from the lesion in the adjacent
metadiaphysis.
• On MRI, chondroblastomas have a lobulated margin.
The signal intensity characteristics are distinct from
those of hyaline cartilage ( i . e . , enchondroma) .
Chondroblastomas appear homogeneously isointense
to muscle on T l -weighted images and heterogeneously
hypo- or isointense to fat on T2-weighted
images. However, the 1 0% to 1 5% of chondroblastomas
with an associated ABC are characterized by
scattered foci of high signal intensity on T2-weighted
Images.

Front 122

A 1 9-year-old woman with an acute injury to the knee.

Back 122

DIFFERENTIAL DIAGNOSIS
• Prior arthroscopic meniscectomy: Meniscal material
in the intercondylar notch following an arthroscopy
would not be expected. Furthermore, the patient has
no history of arthroscopic surgery.
• Bucket handle meniscal tear: The body of the medial
meniscus is truncated and in direct continuity with
meniscal material in the intercondylar notch. On the
axial view, the bucket and its handle can be visualized
as it extends into the intercondylar notch.
• Loose osteochondral fragJ1lents: The linear appearance
of the loose fragment is more in keeping with a
meniscal fragment than osteochondral bodies, which
are typically round or oval in shape. In addition, no
donor site is seen on the available images.
• Anterior cruciate ligament (ACL) injury: The linear
shape of the fragment does not exclude an ACL tear.
However, meniscal tears of this type are not typically
associated with ACL injury.
DIAGNOSIS: Bucket handle meniscal tear.
KEY FACTS
CLINICAL
• This type of meniscal injury may be associated with
rotation of either the femur or the tibia.
253
• There may be associated pain and effusion.
• Patients often present with a locked knee or inability
to extend the knee fully.
RADIOLOGIC
• A thilmed and somewhat truncated appearance to the
body of the meniscus extending into the posterior
horn is characteristic . There may be foreshortening of
the posterior horn without a history of prior
arthroscopy.
• Careful examination of the intercondylar notch typically
reveals the sheared component of the meniscus.
This is often seen beneath the ACL or posterior cruciate
ligament ( PCL) (as in this case, Figure 5- 1 2 C ) ,
producing the double P C L o r double A C L sign.
• In the descriptive term "bucket handle tear," the posterior
horn and body of the meniscus in anatomic
position are analagous to a bucket, whereas the portion
of the meniscus in the notch is analagous to a
bucket handle.
• Tears may also be present within the handle.
SUGGESTED READING
Stoller D, Dillworth W, Anderson LJ. The Knee. In D Stoller (ed),
Magnetic Resonance Imaging in Orthopaedics and Sports
Medicine. Philadelphia: Lippincott, 1995 ; 1 39-372 .

Front 123

A 45-year-old man who was lifting a heavy object when he heard and felt a pop
in his right shoulder.

Back 123

DIFFERENTIAL DIAGNOSIS
• Complete tear of the rotator cuff tendon: The constellation
of findings is consistent with this diagnosis.
There is abrupt termination of the low signal intensity
in the supraspinatus tendon just beneath the acromion.
This is associated with some muscle retraction. At the
expected point of insertion of the supraspinatus tendon
on the humeral head, there is high signal intensity
approaching that of fluid. In addition, fluid is seen in
the subacromial/subdeltoid bursa.
• Partial tear of the rotator cuff tendon: In the case
shown, a full- rather than a partial-thickness tear is present,
as evidenced by high signal intensity equal to the
width of the supraspinatus tendon. The abrupt cut-off
of the low signal intensity in the normal tendon
implies a complete, not partial, tear.
• Tendinopathy: While tendinopathy may show slightly
increased signal intensity on T2-weighted images, it
should not be equal to the signal intensity of fluid and
usually does not involve the entire tendon width.
• Bursitis: Bursitis could produce fluid in the subacromionsubdeltoid
bursa, but the fluid would not be expected
to extend into the glenohumeral space in the presence
of an intact rotator cuff tendon.
DIAGNOSIS: Complete tear of the rotator cuff
tendon.
KEY FACTS
CLINICAL
• Neer believed tl1at impingement and rotator cuff tears
represent a continuum from less severe to most severe
injury. The latter is associated with increasing age and
repetitive activity.
• Impingement is presumed to lead to edema and hemorrhage,
which are reversible changes within the rotator
cuff ( stage I ) . Continued use of the shoulder
causes more fibrosis and tendinitis ( stage I I ) , finally
resulting in a complete or partial tear ( stage I I I ) .
255
• Other investigators have suggested that since bursal
site injuries are more common, rotator cuff tears may
represent tensile strength failure from overuse.
However, botl1 tl1eories suggest that it is a combination
of mechanical factors, repetitive use, age, and
associated degeneration of the cuff.
RADIOLOGIC
• The findings of rotator cuff tears include full-thickness
tendon defect witl1 fluid signal intensity on T2-
weighted images, retraction, tendon atrophy, and fluid
witl1in the subacromial/subdeltoid bursa.
• According to Farley et al . , a full-tl1ickness tendon
defect with fluid signal intensity on T2-weighted imaging,
the accuracy of MR imaging in detecting full
thickness tears is approximately 90%.
• Other associated findings include a hook (type 3 )
acromion, posterior-to-anterior downward sloping of
the acromion, acromioclavicular joint degeneration,
and a thickened coracoacromion ligament with or
without associated spur formation.
SUGGESTED READING
Farley TE, Neumann CH, Steinbach LS, et al. Full thickness tears of
the rotator cuff of the shoulder: Diagnosis with MR imaging.
AJR Am J RoentgenoI 1992 ; 1 58 : 347-35 l .
Neer CS. Anterior acromioplasty for the chronic impingement syndrome:
A preliminary report. J Bone Joint Surg Anl 1972;54:4 l .
Rafii M , Firooznia H , Sherman 0 , et al. Rotator cuff lesions: Signal
patterns at MR imaging. Radiology 1990; 1 77:8 1 7-82 3 .
Stoller DW, Wolfe EM. The Shoulder. In DW Stoller (ed), Magnetic
Resonance Imaging in Orthopaedics and Sports Medicine.
Philadelphia: Lippincott, 1 993;5 1 1-632.

Front 124

A 47-year-old man with a history of right hip pain.

Back 124

DIFFERENTIAL DIAGNOSIS
• Osteoarthritis: WIllie subcortical cysts associated with
osteoarthritis may have areas of high signal intensiry on
T2-weighted images, the absence of plain film findings
and lack of changes on the acetabular side of the joint
argue against this diagnosis.
• Osteochondral injury: The bilateraliry of this process
would be arypical for an osteochondral injury. The
osseous abnormalities also appear farther away from
the articular surface than would be expected. Osteochondral
injuries would be expected to be associated
with secondary degenerative changes, given the size of
the abnormaliry in each femoral head.
• Inflammatory arthritides: This diagnosis is unlikely
given preservation of the joint space on the plain film
and the constellation of findings on MRl.
• Avascular necrosis (AVN): Preservation of the articu-
1ar surface plus the underlying bony abnormalities are
consistent with this diagnosis.
+ DIAGNOSIS: Avascular necrosis of both femoral
heads.
+ KEY FACTS
CLINICAL
• AVN is a consequence of vascular injury resulting in
bone death.
• The causes of AVN are numerous, including drugs
such as corticosteroids and ethanol, marrow replacement
processes such as sickle cell disease and
Gaucher's disease, radiation- or lupus-induced vasculitis,
and embolic etiologies including emboli secondary
to trauma or Caisson disease. Other etiologies, in
which the pathophysiology is less well understood,
include idiopathic disease, Legg-Perthes disease, and
pancreatitis.
• Early diagnosis (i.e., before plain radiographs demonstrate
collapse and subcondylar lucency) is associated
with less morbidiry.
257
• Standard treatment consists of a decompression procedure.
More recently, the placement of vascularized
grafts has been used.
RADIOLOGIC
• MRl has been shown to be more sensitive than both
radionuclide imaging and CT for the detection of early
AVN. This is important since early intervention in
these patients is associated with a better prognosis.
• Abnormalities rypically occur in the weight-bearing
region of the femoral head. The process is bilateral in
40% of cases.
• A well-demarcated serpiginous band of low signal
intensiry is seen on all pulse sequences and is visualized
in approximately 90% of cases. In many cases, T2 -
weighted images reveal a band of increased signal
intensiry along the inner margin of tllis low signal
intensiry band. This is the so-called "double line" sign
of AVN. It is unclear at present whether this represents
a true reactive interface between viable and ischenlic
tissue or simply chemical shift artifact.
• Other associations with AVN include hip effusions (seen
in 85% of cases) and early conversion of hematopoietic
marrow to fatry marrow, especially in men.

Front 125

A 28-year-old man who twisted and injured his knee.

Back 125

DIFFERENTIAL DIAGNOSIS
• Osteochondral injury of the lateral femoral
condyle: This diagnosis is unlikely as the overlying cartilage
appears grossly intact. In addition, the pattern of
edema is more in keeping with an acute injury rather
than a more chronic insult. Finally, this diagnosis does
not explain the other observed abnormalities.
• Acute tear of the anterior cruciate ligament (ACL):
There is discontinuity of the ACL with associated
edema. Other fmdings in keeping with an acute injury
include the bone bruises that occur on both the
femoral condyle and the tibial plateau laterally. In addition,
the edema surrounding the medial collateral ligament
( MCL) injury and the joint effusion suggest an
acute injury.
• Chronic tear of the ACL: While the ACL is indeed
torn, the high signal intensity within it and the high
signal intensity within the lateral osseous structures on
T2-weighted images suggest an acute injury.
• Sprain of the ACL: While there is certainly either or
both edema and hemorrhage within the ACL, the discontinuity
proves that this is more than j ust a simple sprain.
+ DIAGNOSIS: Acute tear of the anterior cruciate
ligament.
+ KEY FACTS
CLINICAL
• The classic mechanism of ACL injury is external rotation
of a minimally flexed femur on a fixed tibia.
• In addition to nonspecific pain and swelling, the
patient often remembers a "popping" sensation during
the traumatic insult.
• A positive drawer or Lochman's sign may be present.
In patients with either or both acute pain and muscle
spasms, these signs may be difficult to elicit.
259
RADIOLOGIC
• The normal ACL has low signal intensity on all pulse
sequences. Discontinuity of the ACL confirms the
diagnosis.
• Thickening of the ACL with high signal intensity
within its fibers and around the ACL also indicate
tendon injury. The high signal intensity may look like
a mass adjacent to the femoral attachment of the
ACL, aptly named the "bulge" sign. The overall accuracy
of MRI in determining tl1e presence of ACL
injury is 95%.
• Osseous injuries are typically associated with acute
tears of the ACL. In one study, 83% of patients with
ACL injuries had "bone bruises" directly over the lateral
femoral condyle terminal sulcus, and 96% had posterolateral
joint injury involving the tibia.
• As with the ACL, discontinuity of the MCL is indicative
of MCL injury. In 30% of MCL tears, there is a
concomitant ACL injury.
SUGGESTED READING
Berquist TH. MRI of the Musculoskeletal System (2nd ed). New
York: Raven, 1990;195-252.
Feagin JA Jr. The Crucial Ligaments (2nd ed). New York: Churchill
Livingstone, 1994;1-38.
Mink JH, Levy T, Crues JV I I I . Tears of the anterior cruciate ligament
and menisci of the knee: MR imaging evaluation.
Radiology 1988; 1 67:769-774.
Speer KP, Spritzer CE, Bassett FH I I I , et al. Osseous injury associated
with acute tears of the anterior cruciate ligament. Am J
Sports Med 1992;20:382-389.
Stoller D, Dillworth W, Anderson LJ. The Knee. In D Stoller (ed),
Magnetic Resonance I maging in Orthopaedic and Sports
Medicine. Philadelphia: Lippincott, 1995 ; 1 39-372 .

Front 126

A 1 6-year-old boy with knee pain and swelling. Plain filins (not shown) are
normal, with the exception of a joint effusion.

Back 126

DIFFERENTIAL DIAGNOSIS
• Synovial sarcoma: These tumors are often para-articular
and associated with calcifications in one-third of
cases (none was present on the plain film in this case ) .
The decreased signal intensity within the synovium is
not typical of a sarcoma.
• Synovial chondromatosis: With this entity, calcifications
are typically visualized on plain film. In addition,
multiple nodules should be seen. In this case, the
abnormality is synovial-based and not multinodular.
• Rheumatoid arthritis: This entity is a synovial process
that may contain hemorrhage. However, it is not typically
a mono-articular arthritis. This patient had no other
symptoms.
• Synovial hemangioma: This entity may have a similar
appearance to the case shown here, although the plain
films often reveal phleboliths. They are commonly
associated with adjacent hemangiomas, which are not
identified in this case.
• Pigmented villonodular synovitis (PVNS): This typically
produces a nodular pattern with areas of hemorrhage
and hemosiderin deposition, as seen in this case.
+ DIAGNOSIS: Pigmented villonodular synovitis.
+ KEY FACTS
CLINICAL
• PVNS is an uncommon synovial abnormality of
unknown etiology. It is not felt to represent a neoplastic
condition, but whether it is an inflammatory or
hyperplastic process due to an unknown stimulus or
the consequence of repeated trauma and hemorrhage
is controversial.
• PVNS is almost always a monoarticular process. The
knee is the most frequently affected joint, involved in
66% to 80% of all cases.
261
• The typical presentation of PVNS is pain, swelling, and
decreased range of motion.
• When fluid is aspirated from the joint, it is usually
serosanguineous, although it may be yellow or chocolate
brown in 30% of cases.
RADIOLOGIC
• On plain films, a joint effusion is typically seen. The
effusion may be of increased density due to hemosiderin
deposition.
• Bony erosions are visualized in 1 5% to 50% of patients,
although these are less frequently seen in joints that
are naturally capacious such as the knee.
• On noncontrast CT, those portions of the synovial
membrane containing hemosiderin often are found to
have high attenuation characteristics.
• On MRI, hemosiderin deposition results in low signal
intensity on both T 1 - and T2-weighted spin echo
images as well as on T1 -weighted gradient-recalled echo
acquisitions. The nodular appearance of the synovium
projecting into a joint effusion is typically seen and reminiscent
of the appearance seen by arthrography.

Front 127

A 1 6-year-old girl with a mass behind her knee of several months' duration.

Back 127

DIFFERENTIAL DIAGNOSIS
• Parosteal sarcoma: This form of osteosarcoma fre quently
occurs i n this location but demonstrates central
ossification rather than calcification. The tumor
is usually connected to the underlying cortex by a
narrow stalk.
• Chondrosarcoma: Central calcification, high signal
intensity on T2-weighted M RI , and cauliflower morphology
are consistent with a cartilaginous tumor.
The large size and marrow invasion indicate a malignant
process.
• Periosteal chondroma: The periosteal location and
high signal intensity on T2 -weighted MRI would be
typical for this benign lesion. The lesions are usually
much smaller in size, however, witl1 infrequent calcification
and no cortical invasion.
• Periosteal Ewing's sarcoma: Saucerization of cortex
may yield a similar radiographic appearance to that
seen in this case. Calcification within the soft-tissue
component, however, would not be expected.
DIAGNOSIS: Peripheral chondrosarcoma.
+ KEY FACTS
CLINICAL
• Chondrosarcomas occur most often in tl1e femur,
pelvis, humerus, ribs, and scapula.
• These tumors are most commonly seen in elderly men.
• Secondary chondrosarcomas may arise from a preexisting
benign cartilaginous lesion.
263
• The incidence of malignancy is increased in hereditary
multiple exostoses and in enchondromatosis ( Oilier's
disease ) .
RADIOLOGIC
• Chondrosarcomas are classified as central or peripheral
depending on the location witl1 respect to the
medullary cavity.
• MRI frequently shows these tumors to have a lobulated
morphology witl1 a high water content due to
tl1e hyaline cartilage matrix.
• Differentiation between benign enchondroma or
osteochondroma and chondrosarcoma Calmot be made
on tl1e basis of the MR signal intensity characteristic
alone. Secondary signs of malignal1CY such as cortical
destruction and the presence of a soft-tissue mass may
be helpful in making this distinction.
SUGGESTED READING
Cohen EK, Kressel HY, Frank TS, et aI. Hyaline cartilage-origin
bone and soft-tissue neoplasms: MR appearance and histologic
correlation. Radiology 1988; 1 67:477-48 l .
Kenan S , Abdelwahab IF, Klein MJ, Herman G . Lesions of juxtacortical
origin (surface lesions of bone ) . Skeletal Radiol 1993;22:
337-357.
Varma DGK, Ayala AG, Carrasco CH, et al . Chondrosarcoma: MR
imaging with pathologic correlation. Radiographies
1 992 ; 1 2 :687-704.

Front 128

A 19-year-old man who lifts weights has persistent pain in his right shoulder.

Back 128

DIFFERENTIAL DIAGNOSIS
• Stress fracture: Focal periosteal reaction without a visible
fracture line suggests the possibility of a stressrelated
injury. Bone marrow edema may be much more
extensive than the size of the cortical abnormality.
• Osteomyelitis: Bone marrow involvement and illdefined
metaphyseal periosteal reaction could represent
evidence of infection. A joint effusion would also raise
the possibility of septic arthritis.
• Ewing's sarcoma: Periosteal reaction could be an
early sign of malignancy. A nidus can be overlooked in
the presence of extensive bone marrow abnormality.
• Osteoid osteoma: In the case shown, a noncalcified
nidus is seen surrounded by reactive bone marrow
edema. The periarticular location is associated with a
reactive joint effusion. This is the most likely diagnosis.
+ DIAGNOSIS: Osteoid osteoma.
+ KEY FACTS
CLINICAL
• The typical history is chronic pain that is worse at night.
265
• The pain is usually relieved by aspirin.
• Osteoid osteomas occur in children and young adults.
• Periarticular lesions may present with premature arthritis
due to chronic reactive synovitis.
RADIOLOGIC
• The nidus, which may be calcified, can be identified
more effectively with CT than M R! .
• Inflammatory changes can b e present i n adjacent bone
marrow and soft tissue, which may mistakenly be taken
as evidence of malignancy.
• Radiographs often show reactive bony sclerosis and
periosteal reaction.
+ SUGGESTED READING
Assoun J, Richardi G, Railhac J-J, et a1. Osteoid osteoma: MR imaging
versus CT. Radiology 1994; 1 9 1 :2 1 7-223.
Hayes CW, Conway WF, Sundaram M. Misleading aggressive MR
i maging appearance of some benign musculoskeletal lesions.
Radiographics 1 992 ; 1 2 : 1 1 1 9- 1 1 34 .

Front 129

A 49-year-old man who fell from a ladder onto his outstretched left hand.

Back 129

DIFFERENTIAL DIAGNOSIS
• Isolated lunate dislocation: This injury can be
excluded by noting the position of the lunate, which is
in contact with the distal radius. With isolated lunate
dislocation, the capitate aligns with the radius, while
the lunate is usually dislocated into the palmar aspect
of the wrist.
• Dorsal perilunate dislocation: This diagnosis would
be correct if no other carpal fractures were identified .
In the illustrated case, the presence of a scaphoid fracture
(or other carpal fracture) indicates a more severe
fracture-dislocation.
• Trans-scaphoid dorsal perilunate fracture-dislocation:
This injury is distinguished from dorsal perilunate
dislocation by the presence of a displaced fracture
through the scaphoid waist. Typically, the proximal
scaphoid fragment remains in anatomic position, adjacent
to the lunate, while the distal fragment travels
dorsally with the remainder of the carpus.
DIAGNOSIS: Trans-scaphoid dorsal perilunate
fracture-dislocation.
+ KEY FACTS
CLINICAL
• The typical mechanism of injury is a fall onto a hyperextended
wrist.
• This type of injury usually requires open reduction,
fracture fixation, and ligamentous repair.
267
• The synonym for this condition is de Quervain)s jracturedislocation.
RADIOLOGIC
• It is important to assess the scaphoid for a fracture when
confronted with an apparent case of carpal dislocation.
• Fundan1entally, the detection of carpal dislocations
relies on recognizing the abnormal relationships of the
carpal bones on properly positioned radiographs.
When patients are badly injured, positioning can be
difficult, with obliquity and various degrees of flexion
and extension leading to distortion and misdiagnosis.
If the distal radius and ulna are properly positioned on
posteroanterior and lateral views, disorganization of
the carpal landmarks usually will be apparent. Obscuration
or overlap of the normal carpal arcs is the sine
qua non of carpal fracture-dislocations.
• Long-term consequences of these injuries include
chronic carpal instability, post-traumatic arthritis, and
osteonecrosis when associated with a scaphoid fracture .
SUGGESTED READING
Berquist TH. Imaging of Orthopedic Trauma. New York: Raven,
1992;827-8 3 1 .
Gilula LA, Yin Y. Imaging o f the Wrist and Hand. Philadelphia:
Saunders, 1996;303-309

Front 130

A 1 7 -year-old girl with a palpable mass in the distal thigh deep to the
quadriceps muscle.

Back 130

DIFFERENTIAL DIAGNOSIS
• Neurofibroma: These fusiform tumors typically infiltrate
nerves in a diffuse fashion. On T2-weighted
MRIs, peripheral high signal intensity myxoid material
surrounds central low signal intensity fibrous tissue in
a concentric fashion.
• Schwannoma: This tumor arises from the nerve
sheath and is usually surrounded by fat within a fascial
plane. Irregular, internal low signal intensity areas are
commonly seen on T2-weighted MRIs.
• Hemangioma: These tumors have large, vascular
channels that are high signal intensity on T2-weighted
MRIs. The mass may have multiple lobulated compartments
that are separated by fibrous septae. Focal
thrombi or phleboliths may be seen internally without
evidence of rapid flow or hemorrhage.
• Ganglion cyst: Although high signal intensity juxtaarticular
lesions may contain septations on T2-weighted
MRIs, the internal architecture is otherwise homogeneous,
without focal areas of decreased signal intensity.
Therefore, this is an unlikely diagnosis.
+ DIAGNOSIS: Soft-tissue hemangioma.
+ KEY FACTS
CLINICAL
• These lesions may occur within muscle, fascial planes,
or subcutaneous tissues.
• Hemangiomas may be difficult to diagnose in the
absence of cutaneous manifestations.
269
• Intramuscular hemangiomas may be an occult cause of
muscle pain. Hemangiomas are seen in Maffucci syndrome
associated with multiple enchondromas.
RADIOLOGIC
• Hemangiomas are one of the benign lesions that can
often be distinguished definitively from malignant softtissue
masses.
• A histologic diagnosis can be made if calcified phleboliths
are seen on plain radiographs.
• The diagnosis of hemangioma can be strongly suggested
if small, high signal intensity compartments are seen on
T2-weighted MRIs with internal low signal areas representing
thrombi (see Figure 5-20B).
+ SUGGESTED READING
Burk DL Jr, Brunbcrg JA, Kanal E, et al. Spinal and paraspinal neurofibromatosis:
Surface coil MR imaging at 1 . 5 T. Radiology
1987;1 62:797-80 1 .
Cohen EK, Kressel HY, Perosio T, et al. MR imaging of soft-tissue
hemangiomas: Correlation with pathologic findings. AJR Am J
Roemgenol 1988;1 50: 1 079- 108 1 .
Moulton JS, Blebea JS, Dunco DM, et al. MR imaging of soft-tissue
masses: Diagnostic efficacy and value of distinguishing between
benign and malignant lesions. AJR Am J Roemgenol 1 99 5 ; 1 64 :
1 1 9 1 -1 199.

Front 131

A 43-year-old woman with morning stiffness, pain, and swelling in the joints of the
wrists and fmgers bilaterally.

Back 131

DIFFERENTIAL DIAGNOSIS
• Gouty arthritis: The erosions involving the left
scaphoid have an appearance that could represent gout,
with fairly defined margins and edges that appear to be
overhanging. Gout is unlikely for multiple reasons,
including the extensive joint space narrowing in the
wrists, the juxta-articular osteoporosis, and the fact that
this is a relatively young woman with no known disorder
or enzymatic defect that would predispose to gout.
• Rheumatoid arthritis: This diagnosis is overwhelmingly
favored in a female patient with bilateral symmetrical
erosive disease involving the wrists,
metacarpophalangeal (MCP) joints, and proximal
interphalangeal ( PI P ) joints. The presence of juxtaarticular
osteoporosis and the absence of reactive
bone formation also favor this diagnosis.
• Psoriatic arthritis: This is unlikely given the sparing
of the distal interphalangeal ( DI P ) joints, the bilateral
symmetrical distribution, and the lack of proliferative
changes.
DIAGNOSIS: Rheumatoid arthritis.
KEY FACTS
CLINICAL
• Rheumatoid arthritis has a female prominence and
tends to involve young to middle-aged individuals.
271
• The "morning gel" ( i . e . , morning stiffness) phenomenon
is typical.
• The rheumatoid factor is positive (seropositive) .
• Subcutaneous nodules are present i n 2 5 % o f patients.
RADIOLOGIC
• The hands and wrists are the most common target
sites. Distribution is typically bilateral and symmetric..l.
• In the digits, MCP joints are typically involved earlier
and more severely than PIP joints. On the other hand,
PIP joints are typically involved earlier and more
severely than DIP joints, which may be spared.
• Periarticular soft-tissue swelling, juxta-articular osteoporosis,
marginal erosions, and uniform joint space
narrowing are typical early findings.
• A striking lack of reactive proliferative bone formation
is typical.
• The feet are commonly involved. Large joints of the
appendicular skeleton may also be involved.
• Involvement of the axial skeleton most commonly
affects the cervical spine, particularly the upper portion,
often resulting in atlantoaxial subluxation.
• SUGGESTED READING
Brower AC. Arthritis in Black and White. Philadelphia: Saunders,
1988;1 37-165.
Resnick D, Niwayama G . Diagnosis of Bone and Joint Disorders
(2nd ed) . Philadelphia: Saunders, 1989;955-1 067.

Front 132

A 62-year-old, previously healthy woman presents with a I -week history of chills,
fever, and left hip pain of such severity that she is unable to walk. A pelvic radiograph
and a left hip arthrogram/aspiration are negative. A bone scan revealed
increased activity in the left sacroiliac joint.

Back 132

DIFFERENTIAL DIAGNOSIS
• Unilateral septic sacroiliitis: The negative radiograph
and positive bone scan indicate a sacroiliac joint
process. The joint fluid, capsular distention, and irregular
joint space on MRl reflect an articular process.
The marked and diffuse marrow edema and iliacus
muscle abscess are most consistent with an infectious
sacroiliitis.
• Unilateral seronegative sacroiliitis: This entity has a
more insidious onset than in the case presented. There
may be a prior history of a seronegative arthropathy.
There is much less subchondral edema than in the case
shown. The myositis and abscess formation are more
typical of septic sacroiliitis.
• Ewing's sarcoma and lymphoma: These neoplasms
often present in young patients ( i . e . , at the same age
as septic sacroiliitis) . They target the marrow of the
iliac bone adjacent to the sacroiliac joint.
Unfortunately, this misdiagnosis is not uncommon. As a rule, the joint space is normal, and the epicenter
of the tumor is in the iliac tuberosity and may extend
to the posterior ligaments of the joint. Furthermore,
it is often associated with a large soft tissue mass.
+ DIAGNOSIS: Unilateral septic sacroiliitis.
+ KEY FACTS
CLINICAL
• This entity accounts for only 1 % to 2% of all cases of
septic arthritis and osteomyelitis. For example, in
1 988, only 1 66 cases were reported. Before antituberculous
drugs, tuberculosis (TB ) of the sacroiliac joints
was 1 0 times more common.
• This disorder is often not suspected clinically because
of the lack of localizing symptoms, unfamiliarity with
the variability of presentation, and an incomplete physical
examination.
• Septic sacroiliitis is very often misdiagnosed initially.
• Acute onset of fever and pain in the ipsilateral hip are
present in 75% of patients.
• A delayed diagnosis is associated with increasesd morbidity
and rate of complications, including abscess formation,
osteomyelitis, and ankylosis.
• In 60% of patients, there is an associated preexisting
condition, such as a focus of infection (skin: 8%; lung:
5%; ear, nose, and throat: 5%; gastrointestinal tract:
4%; gynecologic: 4%; and intravenous [ IV] drug abuse:
1 3% ) or trauma ( 6% ) .
• I t is most often seen i n young males (60%) , with an
average age of 22 years.
• The erythrocyte sedimentation rate is almost uniformly
elevated.
• The most common infecting organism is Staphylococcus
aureus. Pseudomonas aeruginosa is essentially only seen
in IV drug abusers. Organisms may be obtained from
blood cultures (23%), image-guided sacroiliac joint
273
aspiration ( 50% to 88%), or by open biopsy. An organism
is not identified in 25% of cases.
• Treatment includes high doses of oral and IV antibiotics.
Surgery is occasionally needed for open biopsy
or abscess drainage.
RADIOLOGIC
• Plain radiographs are usually insensitive and misleading
in early stages because of obscured anatomy and lack of
soft-tissue detail. Later, widening of the joint space and
superficial erosions with some reactive sclerosis may be
seen. After treatment, subchondral sclerosis increases,
the joint becomes narrow, and 20% will ankylose. An
abscess with calcification strongly suggests TB.
• Bone scintigraphy is more sensitive than plain radiography.
It is the ideal modality for identifying a suspected
infectious process because localizing signs are
typically poor and, as a rule, unilateral. False-negative
studies are possible, such as in bilateral sacroiliitis or in
infants. Scintigraphy is also better than MRl for initial
evaluation.
• CT is more sensitive than plain radiography and is particularly
good for defining erosive changes. Falsenegative
studies are uncommon. IV contrast material is
essential for diagnosing an abscess. CT is usually
reserved for guiding needle aspiration of the joint or
percutaneous abscess drainage.
• On M Rl , the infected and inflamed sacroiliac, synovial,
and articular cartilages are typically accompanied by a
joint effusion and distention of the capsule. In contrast
to unilateral seronegative sacroiliitis, subchondral
edema is prominent and diffuse on both sides of the
joint. This results in decreased signal intensity on T l weighted
images and increased signal intensity on T2-
weighted images, short tau inversion recovery (STIR),
and post-gadolinium images. As with seronegative
spondyloarthropathies, fluid in the joint with a distended
anterior capsule is often noted on T2-weighted
images. Unique to septic sacroiliitis is the fact that the
adjacent muscles ( iliacus, psoas, and gluteus) are
inflamed. Focal, very intense signal intensity in the
marrow on T2-weighted images and on T l -weighted
post-gadolinium images suggests osteomyelitis.

Front 133

A 1 2-year-old boy with a painless palpable mass along the lateral aspect of the left knee.

Back 133

DIFFERENTIAL DIAGNOSIS
• Telangiectatic osteosarcoma: This predominantly
lytic lesion may demonstrate hemorrhage and fluidfluid
levels. However, these lesions usually have more
destructive and aggressive features than the case shown
here.
• Simple bone cyst: Fluid-fluid levels may be seen in
bone cysts. These lesions, however, do not usually
expand the cortex to a significant degree.
• Aneurysmal bone cyst: These expansile lesions are
characterized by multiple compartments containing
internal fluid-fluid levels on M R! . Extracellular methemoglobin
( high signal intensity) in the supernatant
contrasts with intracellular methemoglobin (low signal
intensity) within intact, dependent red blood cells.
• Fibrous dysplasia with cystic degeneration: With
these lesions, cyst formation may occur with expansion
of the cortex and fluid-fluid levels. A ground-glass
appearance is often noted in the noncystic portions of
the lesion.
+ DIAGNOSIS: Aneurysmal bone cyst.
+ KEY FACTS
CLINICAL
• Aneurysmal bone cysts occur in pediatric patients and
young adults.
275
• These lesions may present with a pathologic fracture .
• An enlarging palpable mass may be painless, as in this
patient.
• The location is usuaUy the meta diaphyseal region of
long bones, but the pelvis and spine may also be
involved.
RADIOLOGIC
• The typical appearance is an expansile lytic lesion surrounded
by a thin shell of bone.
• Multiple small compartments are usually seen with a
layered hematocrit effect due to previous hemorrhage.
• Fluid-fluid levels can also be seen with CT, but after
positioning, a short waiting period before scanning is
needed to aUow layering to occur and the fluid-fluid
level to be shown.
• SUGGESTED READING
Beltran J, Simon DC, Levy M, et aI. Aneurysmal bone cysts: MR
imaging at 1 .5T. Radiology 1 986; 1 58 :689-690.
Hudson TM. Fluid levels in aneurysmal bone cysts: A CT feature.
AJR Am J Roentgenol 1984; 1 4 1 : 1 00 1 - 1 004.
Tsai JC, Dalinka MK, Fallon MD, et aI. Fluid-fluid level: A nonspecific
finding in tumors of bone and soft tissue. Radiology
1 990; 1 75 :779-782.

Front 134

A 39-year-old woman with bilateral hip pain. She has a prior history of precocious
puberty and a left scaphoid fracture.

Back 134

DIFFERENTIAL DIAGNOSIS
• Neurofibromatosis: Although rare, precocious sexual
development has been reported with neurofibromatosis.
Neurofibromatosis can cause bone lesions with
changes in bone density and shape, but the bone
lesions in the case shown are atypical in distribution
and appearance for neurofibromatosis.
• Metastatic disease: This diagnosis is unlikely because
there is no history of a primary malignancy and there
is relative sparing of the spine.
• Fibrous dysplasia: This is the most likely diagnosis
given the expansile lesions of the ribs, the mixed lucent
and sclerotic lesions of the pelvis and proximal femurs,
the "shepherd's crook" deformity of the right femur,
and the somewhat more pronounced overall involvement
on the left side of the body. The history of precocious
puberty and cafe-au-lait spots would fit with
McCune-Albright syndrome.
• Paget's disease: This diagnosis is unlikely given the
patient's age, relative sparing of the epiphyseal regions
in the proximal femurs, and lack of classic pattern of
enlargement of bone, trabecular coarsening, and cortical
thickening.
+ DIAGNOSIS: McCune-Albright syndrome with
polyostotic fibrous dysplasia.
+ KEY FACTS
CLINICAL
• The classic triad for McCune-Albright syndrome
includes: ( 1 ) polyostotic fibrous dysplasia with a unilat-
277
eral tendency, ( 2 ) cafe-au-lait spots, and ( 3 ) precocious
puberty. This syndrome was originally described in
female patients.
• McCune-Albright syndrome is not a familial condition.
• Proximal femoral deformities can result in limb shortelung
or a limp or be painful. Fractures are the most
common complication .
RADIOLOGIC
• The lesions of fibrous dysplasia have variable density.
• A ground-glass appearance is typical. There is often a
sclerotic rim or rind.
• Endosteal scalloping and bone expansion may occur.
• Common sites of involvement include the ribs femur
tibia, pelvis, and skull. Vertebral involvement i.. rare.
'
There is a unilateral predominance .
• A shepherd's crook deformity o f the proximal femur is
classic.
• In the skull, the outer table is involved earlier and
more extensively than the ilmer table. There is also
sclerosis at the base of the skull.
+ SUGGESTED READING
Edeiken J . Roentgen Diagnosis of Diseases of the Bone ( 3rd ed)
(vol I I ) . Baltimore: Williams & Wilkins, 1 9 8 1 ;994-1 027.
Kransdorf MJ, Moser RP Jr, Gilkey FW. Fibrous dysplasia.
Radiographies 1990; 1 0:5 1 9-537.
Mirra JM, Gold RH. Fibrous Dysplasia. In JM Mirra, P Piero, RH
Gold (eds), Bone Tumors. Philadelphia: Lea & Febiger,
1 989; 1 9 1-226.
Resnick D, Niwayama G. Diagnosis of Bone and Joint Disorders
(2nd ed). Philadelphia: Saunders, 1 988;4057-4072.

Front 135

A 6 1 -year-old man presents with right hip pain. His prostate is enlarged on
physical examination.

Back 135

DIFFERENTIAL DIAGNOSIS
• Skeletal metastasis from prostate carcinoma:
Metastasis is a consideration given the fact that there
are multiple abnormal foci on the bone scan and a
sclerotic lesion in the pelvis. However, the diagnosis is
unlikely given the pattern of trabecular coarsening and
cortical thickening and extensive involvement of one
innominate bone without disease elsewhere in the axial
skeleton.
• Myelofibrosis: This entity is unlikely given the asymmetric
involvement.
• Mixed phase of Paget's disease: This is the best diagnosis
because of its typical location in the innominate
bone, bone enlargement, mixed lucency and sclerosis,
trabecular coarsening, cortical thickening, and a positive
bone scan.
+ DIAGNOSIS: Mixed-phase Paget's disease of the
right innominate bone.
+ KEY FACTS
CLINICAL
• Paget's disease occurs in middle-aged to elderly subjects,
and more commonly in men.
• The most common complication is a pathologic fracture.
Bowing of bones may also occur.
• Other complications include spinal stenosis, cranial
nerve compression, and degenerative joint disease .
279
• Secondary neoplasms may develop, such as sarcomatous
transformation ( < l %) and giam cell tumors ( also
uncommon) .
RADIOLOGIC
• Three phases are recognized in Paget's disease: lytic,
mixed, and sclerotic. Bone scintigraphy shows
intensely increased activity in the lytic and mixed
phases, and a variable pattern in the sclerotic phase.
• The disease tends to progress from one end of a long
bone toward the other, sometimes with an advancing
lytic edge having a flame-shaped or blade-of-grassshaped
margin.
• The lytic phase may show regional lucency in the
skull and flat bones, which is known as osteoporosis
circumscripta.
+ SUGGESTED READING
Lakhanpal S, O'DuffY JD. Paget's disease and osteoarthritis.
Arthritis Rheum 1986;29 : 1 4 1 4- 1 4 1 5 .
Mirra JM, Brien EW, Tehranzadeh J . Paget's disease o f bone:
Review with emphasis on radiologic features. Parts I and II.
Skeletal Radiol 1 995;24 : 1 63-1 7 1 (part I ) , 1 73-1 84 (part II).
Moore T, King A, Kathol M, et al. Sarcoma in Paget disease of
bone: Clinical, radiologic and pathologic features in 22 cases.
AJR Am J RoentgenoI 1 99 1 ; 1 56: 1 1 99-1 2 0 3 .

Front 136

A 25 -year-old hitchhiker who was struck in the back of the head by a trucker's
side mirror.

Back 136

DIFFERENTIAL DIAGNOSIS
• Hyperflexion sprain: Hyperflexion sprain is characterized
by focal angulation of the spine and widening of
the interspinous distance. On the anteroposterior (AP )
view, the spinous process would not be deviated from
the midline, which distinguishes it from unilateral
interfacetal dislocation ( U I D ) .
• Bilateral interfacetal dislocation ( BID): This severe
cervical spine injury is distinguished from hyperflexion
sprain by complete disruption of all ligamentous
integrity at the injured level. BID is, therefore, a
grossly unstable injury. It is distinguished from unilateral
interfacetal dislocation by a lack of rotation of the
spinous process on the AP view and by significant
anterolisthesis ( usually ..50%) of one vertebral body on
the subadjacent vertebra.
• UID: UID injuries are produced by flexion and rotation
of the spine. The rotational component leads to a
unilateral dislocation of the cervical apophyseal joint.
The unilateral dislocation can be identified by displacement
of the spinous process of the affected vertebra
toward the side of the dislocation. Oblique views of
the cervical spine also demonstrate the site of UID.
+ DIAGNOSIS: Unilateral interfacetal dislocation
on the right.
+ KEY FACTS
CLINICAL
• The mechanism of injury is fundamentally flexion with
rotation.
• This injury should be approached initially as unstable
but may later prove to be mechanically stable if the
ipsilateral fracture is minimal and the contralateral ligaments
are intact. Based on review of the initial radiographs,
such distinctions can be difficult and, for
patient safety, it is best to consider these injuries as
unstable until proven otherwise.
281
• Profound neurologic deficits are rare in patients with
UID injuries, but radiculopathy is common.
RADIOLOGIC
• B I D is characterized by a traumatic anterolisthesis of
..50%. In UID injuries, the degree of anterolisthesis is
constrained by the nondislocated side with anterolisthesis
in the range of 25%. There may be slight angular
deformity and fanning of the involved spinous
processes on the lateral film. On the AP view, deviation
of the spinous process of the involved vertebra
toward the side of the dislocated facet is characteristic.
• In patients with a hyperflexion sprain injury, rotational
abnormalities of the spine are not noted on either AP
or lateral views. Typically, the degree of posterior ligamentous
injury in patients with hyper flexion sprain is
less than that in patients with UID. Nonetheless, some
patients with a hyperflexion sprain injury have severe
ligan1entous damage that remains w1detected for some
time, and they can present with frank instability days
to weeks after the initial trawna ( delayed instability). It
is for this reason that all hyperflexion sprain injuries
should be considered as important soft-tissue injuries
requiring both clinical and radiographic follow-up
within 5 to 10 days of injury.
+ SUGGESTED READING
Berquist TH. Imaging of Orthopedic Trauma. ew York: Raven,
1992 ; 1 2 3- 1 69 .
Harris JH, Harris WH, Novelline RA. The Radiology of Emergency
Medicine. Baltimore: Williams & Wilkins, 1993;1 77- 1 79 .

Front 137

Patient A: a 25-year-old woman involved in a head-on motor vehicle accident.
Patient B : a 30-year-old sign painter who fell 30 feet from a scaffold, landing on
his right leg.

Back 137

DIFFERENTIAL DIAGNOSIS
• Lateral compression injury: Lateral compression
injuries are relatively uncommon but can be confused
with vertical shear injuries. The two injuries are usually
distinguished by the oblique orientation of the fractures
in lateral compression injury and the cephalad
displacement of the hemipelvis in vertical shear injury.
• Anteroposterior compression injury: This mechanism
usually produces mirror image fractures of the
pubic rami or traumatic diastasis of the symphysis
pubis. In the posterior pelvis, one usually sees bilateral
traumatic diastasis of the sacroiliac joints. The so-called
"open book pelvis" is an example of an AP compression
injury.
• Vertical shear injury (formerly known as Malgaigne
fracture dislocation): This injury is produced by a
forceful axial load on the hemipelvis that might occur
from a fall onto one leg, as in patient B. A distinguishing
feature of vertical shear injuries is the cephalad displacement
of the hemipelvis, which is separated from
the remainder of the pelvis by anterior and posterior
ring disruptions.
+ DIAGNOSIS: Vertical shear injury.
+ KEY FACTS
CLINICAL
• This injury occurs when there is a vertical force
directed along the axis of the femur.
283
• The physical examination can incorrectly suggest a
hip dislocation.
RADIOLOGIC
• Vertical shear injury is caused by two disruptions of
the pelvic ring, one anterior to the acetabulum and the
other posterior to the acetabulum.
• The posterior disruption can occur through the sacral
ala, sacroiliac joint, or posterior ilium. The anterior
disruption can occur through the symphysis pubis,
superior and inferior pubic rami, or acetabulum.
• The exact site of the anterior or posterior disruption is
unimportant because any combination of pelvic disruptions
from a vertical shear mechanism will produce an
unstable, elevated hemipelvis.
• Lateral compression injuries can have a superficial
resemblance to vertical shear injuries; however, cephalad
displacement of the hernipelvis is not seen in lateral
compression injuries.
• Distinction among anteroposterior compression, vertical
shear, and lateral compression injuries is occasionally
problematic. Furthermore, mixed injuries can
occur.
SUGGESTED READING
Berquist TH. Imaging of Orthopedic Trauma. New York: Raven,
1992;227-239.
Harris JH, Harris WH, Novelline RA. The Radiology of Emergency
Medicine. Baltimore: Williams & Wilkins, 1993;693-764.

Front 138

A 66-year-old woman with chronic obstructive pulmonary disease ( COPD) and
back pain.

Back 138

DIFFERENTIAL DIAGNOSIS
• Senile osteoporosis: Intravertebral vacuum phenomenon
may occur with this form of osteoporosis in a
patient taking corticosteroids for COPD due to significant
trauma or intraosseous prolapse of a vacuum disc.
Concave endplates are often present.
• Multiple myeloma: The presence of a vacuum phenomenon
in a collapsed vertebral body does not
exclude malignancy as in multiple myeloma. Cortical
destruction rather than subchondral endplate sclerosis
would be expected.
• Gaucher's disease: Osteoporosis and multiple compression
fractures are common with Gaucher's clisease.
Vertebra plana deformities may occur at multiple levels,
but vacuum vertebral boclies are not typical.
• Corticosteroid-induced osteoporosis: This clisorder
is associated with peripheral condensation of bone at
the site of endplate compression deformities. Vacuum
vertebral boclies can be seen secondary to osteonecrosis.
This is the most likely cliagnosis for the case
shown.
+ DIAGNOSIS: Corticosteroid-induced osteoporosis
and vertebral osteonecrosis.
+ KEY FACTS
CLINICAL
• This conclition may be caused by either Cushing's disease
or exogenous corticosteroids.
285
• Endogenous Cushing's clisease results from adrenal
hyperplasia, adrenal adenoma or carcinoma, or ectopic
adrenocorticotropic hormone-producing tumors.
• Increased bone resorption results in negative calcium
balance and hypercalciuria.
• The bony manifestations may be accentuated in elderly
women who have an underlying chronic clisease .
RADIOLOGIC
• Subchondral endplate sclerosis is a result of inappropriate
exuberant callus formation .
• The intravertebral vacuum phenomenon is most common
at the thoracolumbar junction.
• The vacuum phenomenon is bordered frequently by sclerotic
bone, suggesting the presence of a pseudoarthrosis.
+ SUGGESTED READING
Kumar R, Guinto FC Jr, Madewell JE, et al. The vertebral body:
Radiographic configurations in various congenital and acquired
disorders. Radiographies 1 988;8 :455-485.
Kumpan W, Salomonowitz E, Seidl G, Wittich GR. The intravertebral
vacuum phenomenon. Skeletal Radiol 1 986; 1 5 :444-447.
Resnick D. Bone and Joint Imaging. Philadelphia: Saunders,
1 989;650-65 1 .

Front 139

A 50-year-old man with low back pain.

Back 139

DIFFERENTIAL DIAGNOSIS
• Giant cell tumor: The location of the lesion and radiographic
appearance are compatible with this diagnosis.
However, the patient's age makes this diagnosis unlikely,
as giant cell tumor is usually seen in young adults.
• Metastatic disease: The age and radiographic appearance
favor this diagnosis, especially for renal cell or
thyroid carcinoma metastases. Renal cell carcinoma
metastases, in particular, may be "cold" on a delayedphase
bone scan due to hypervascularity. The lack of
other lesions, however, lowers the likelihood of this
diagnosis.
• Primary malignant bone tumor: Chondrosarcoma
and fibrosarcoma are possible considerations in this
age group and may have a similar radiographic appearance.
Chondrosarcoma, in particular, may occur in this
location. However, chondrosarcoma would be
expected to have a very bright signal on T2 -weighted
MRI (i.e., brighter than the abnormal signal seen in
this case) due to the presence of chondroid matrix.
• Brown tumor: The radiographic appearance is compatible
with this diagnosis, but there is no concomitant
evidence or history of hyperparathyroidism.
• Solitary myeloma: The patient's age and the radiographic
appearance of the lesion are compatible with
this diagnosis.
• Fibrous dysplasia: Fibrous dysplasia typically demonstrates
some increased uptake of tracer on a bone scan.
Although the radiographic appearance of this lesion is
compatible with this diagnosis, these lesions are usually
healed by age 50.
DIAGNOSIS: Solitary myeloma (plasmacytoma).
+ KEY FACTS
CLINICAL
• This rare entity represents <5% of all plasma cell dysplasias.
It tends to affect a younger population ( mean
age of 50 years) than multiple myeloma.
• Criteria for diagnosis are:
Histologic proof
Complete skeletal survey excluding other lesions
Negative bone marrow biopsy
287
Absence of dysproteinemia and Bence-Jones proteinuria
(or if M -spike is present, disappearance
after resection of the solitary lesion)
• The treatment is en bloc excision and radiation therapy.
• The clinical prognosis is much better than in multiple
myeloma, even in those patients who eventually
develop multiple lesions.
• The existence of this entity is controversial, and very
few true cases are reported. At least 70% of patients
presenting with solitary myeloma eventually progress
to multiple myeloma.
RADIOLOGIC
• Plasmacytomas are variable in appearance. The lesions
may be purely lytic without expansion, or bubbly and
expansile with thickened trabeculae. Sclerotic plasmacytoma
has also been reported. Calcifications may be present
in plasmacytoma and can mimic chondrosarcoma.
• The most common sites of involvement are the vertebral
bodies, pelvic bones, and shoulder girdle .
• When plasmacytoma occurs i n the spine, it i s often
associated with a gibbous deformity and can cross the
disk spaces.

Front 140

A 14-year-old girl with morning headaches and papilledema

Back 140

Craniopharyngioma: This diagnosis might be considered
because the lesion is located in the midline near
the suprasellar region. However, craniopharyngiomas
are typically located in the suprasellar cistern or, on
occasion, within the sella. They rarely originate in the
third ventricle, although they can compress the third
ventricle from below.
• Arachnoid cyst: This diagnosis might be considered
because the lesions shown above are round, raising the
possibility that they are cysts. However, arachnoid cysts
are isodense with cerebrospinal fluid (CSF) on CT and
are isointense on MRI, unlike the lesions shown above,
making this an incorrect diagnosis.
• Meningioma: This entity can occasionally occur
within the third ventricle. The hyperintense appearance
on T l -weighted images would be very unusual,
although it is conceivable that a densely calcified
meningioma would be T l - bright and T2-dark.
Furthermore, contrast enhancement would be
expected in the case of meningioma but was not present
in the lesions shown above.
• Dermoid cyst: This diagnosis might be considered
because the lesions shown above are located in the
midline, a feature that is typical of dermoid tumors.
However, dermoid cysts are typically hypo dense on CT
relative to CSF due to their fat content, and are typically
inhomogeneous on MR images.
• Colloid cyst: This lesion is commonly slightly hyperdense
on noncontrast CT, hyperintense on noncontrast
Tl -weighted MR images, and hypointense on T2 -
weighted images. This is the correct diagnosis.
DIAGNOSIS: Colloid cyst.
+ KEY FACTS
CLINICAL
• Colloid cysts are benign neoplasms that account for
< l % of intracranial neoplasms.
• These lesions are usually discovered in adolescence or
young adulthood. The typical presentation is that of
episodic symptoms or signs of increased intracranial
pressure due to obstructive hydrocephalus. The
headache is often positional (e.g., worsened by leaning
forward ).
• Colloid cysts are almost always located in the anterosuperior
portion of the third ventricle and produce
symptoms by intermittent ventricular obstruction at
the level of the foramen of Monro.
• These lesions are thin-walled, well-circumscribed,
round structures with various degrees of attachment to
the roof of the third ventricle.
291
• Colloid cysts are thought to be a form of neuroepithelial
cyst, produced by abnormal folding of the neuroepitllelium
in the anterior portion of the third
ventricle during embryogenesis. More specifically, they
are thought to be derived from the paraphysis, a
stalked protuberance of extraventricular choroid plexus
that is derived from the neuroepithelial lining of the
roof of the diencephalon.
• Contents of colloid cysts include mucinous substances
(including secretory products, such as fat and cholesterol
crystals), hemorrhagic products, and variable degrees of
ions, such as CaiCiunl, magnesium, and sodium.
• Various treatments are available, including treatment of
hydrocephalus alone (via biventricular shunt placement),
cyst aspiration via stereotactic guidance, and
surgical excision.
RADIOLOGIC
• On CT, colloid cysts are typically hyperdense relative
to CSF due to their mucinous contents. They are typically
homogeneous.
• Variable degrees of obstructive hydrocephalus can be
seen. Because the lesion is located in the anterior portion
of the third ventricle, only the lateral ventricles
would be expected to be enlarged.
• Calcification is rare and considered a finding that
makes the diagnosis of colloid cyst less likely.
• Mild contrast enhancement can be seen occasionally,
but dense enhancement is not a feature of these
lesions.
• MRI can be used for localizing the lesion to the anterior
third ventricle rather than adjacent sites such as
the hypothalamus, optic tract, or suprasellar cistern.
• On MRI, the cyst will be seen to differ in signal intensity
from CSF on one or more pulse sequences. The
cysts are often hyperintense relative to CSF on T l weighted
sequences due to the mucinous contents
and, possibly, presence of cholesterol crystals. Less
commonly, they are hypointense to CSF on T2-
weighted images, possibly due to paramagnetic properties
of ions contained witlun the cyst fluid.

Front 141

A 26-year-old woman with acquired immunodeficiency syndrome (AIDS) and
deteriorating mental status.

Back 141

DIFFERENTIAL DIAGNOSIS
• Toxoplasmosis: This diagnosis might be considered
because it is common in AlDS patients. Although
lesions can occur anywhere in the brain, a more central
location (in the periventricular regions) is typical.
Furthermore, lesions generally contrast-enhance and
have edema and mass effect, making this an unlikely
diagnosis.
• Lymphoma: Primary B cell central nervous system
( CNS) lymphoma is also relatively common in AlDS
patients. However, in the immunocompromised
patient, ring enhancement is typically and frequently
accompanied by edema and mass effect. These features
make lymphoma an unlikely diagnosis.
• Cryptococcosis: Cryptococcal infection is common III
AlDS patients and can have a number of radiologic
appearances: meningeal enhancement (due to menmgitis)
, nonenhancing (or rim-enhancing) masses typically
occurring in tlle basal ganglia (so-called gelatinous
pseudocysts) , ring-enhancing parenchymal masses
(cryptococcomas) , and intraventricular masses.
onenhancing lesions lacking mass effect would be
distinctly unusual.
• Infarction: I nfarctions can occur m the periphery of
the brain, usually m a setting of embolic infarction.
However, the distribution of these lesions-i.e., abrupt
termination at the gray-white junction with sparing of
the cortex-would be very unusual for infarction .
I nstead, both gray and white matter would be expected
to be ll1Volved. This is an unlikely diagnosis.
• Progressive multifocal leukoencephalopathy (PML):
The typical appearance of PML is that of one or more
non enhancing white matter lesions lacklllg mass effect
in an immunocompromised host. This is tlle correct
diagnosis.
• DIAGNOSIS: Progressive multifocal leukoencephalopathy.
KEY FACTS
CLINICAL
• PML is due to an oligodendroglial infection by the
human papovavirus (also known as tlle JC virus, the
initials of the patient in whom it was first described).
The JC virus remains latent until reactivated by an
immunodeficient state.
293
• This infection occurs primarily in immunocompromised
patients. It occurs in 1 % to 4% of adult AIDS
patients but is extremely rare m children. Organ transplant
recipients are another non-AlDS group at
increased risk of acquiring the infection.
• Symptoms include visual deficits and cranial nerve
palsy, focal neurologic deficits such as motor weakness
and sensory loss, and nonfocal neurologic symptomse.
g., encephalopathy or headache.
• The diagnosis should be considered m advanced cases
of AlDS. The prognosis is very poor. There is no
proven effective therapy, and deatll typically occurs
witlWl months of the onset of symptoms.
RADIOLOGIC
• On CT, lesions can be seen as nonenhancing, hypodense
white matter lesions lacklllg mass effect. MRl is superior
to CT in displaying the number and size of lesions.
• Lesions are frequently bilateral but distributed m an
asymmetric manner between the hemispheres. The
posterior centrum semiovale is the most common location.
The subcortical white matter is affected initially.
With the development of deep white matter lesions,
large confluent lesions can result. External capsule and
posterior fossa involvement is less common and can
occur in the absence of centrum semiovale lesions.
• The absence of mass effect or contrast enhancement is
a characteristic feature. Faint peripheral enhancement
can be seen rarely. Nonetheless, the lack of contrast
enhancement or mass effect is a useful findffig in distinguishing
PML from other AlDS-related lesions.
• Involvement of the basal ganglia and other gray matter
structures is explained by contiguous involvement
of white matter lesions and/or infiltration of myelinated
white matter fibers that course through the
basal ganglia.
• Cavitary changes can be seen as a late manifestation of
PML.

Front 142

A 16-year-old boy with lethargy, confusion, and increasing thirst and urination.

Back 142

Primary eNS lymphoma: This diagnosis would be
considered because of the presence of multiple hyperdense
masses. However, this would be an unlikely
diagnosis in a child because most affected patients are
in late adulthood (with the exception of immunocompromised
patients, who can be affected at any age).
• Pineo blastoma: This tumor is a consideration when a
pineal region tumor is seen in a child. Although these
tumors are often large (>4 cm), they have an irregular
contour, and are inhomogeneous, unlike the lesion
FIGURE 6-3B Image at a more caudal level fr om the same noncontrast
CT shows a hyperdense mass in the suprasellar cistern.
shown in this case. This diagnosis would not account
fo r the suprasellar mass, although it is conceivable that
it could represent a metastasis from pineoblastoma.
• Germinoma: These tumors appear slightly hyperdense
on CT, are smoothly contoured, and 95% are in the
pineal or suprasellar region. Furthermore, this is the
only tumor that might be expected to be fo und in
both the pineal and suprasellar regions simultaneously.
• Metastases: Intracranial metastases are rare in childhood
. The overwhelming majority of intracranial
tumors are primary in origin. Furtllermore, tlle vast
majority of metastases would be hypodense, or occaCASE
#3 N euroradiology
sionally isodense, on noncontrast CT and usually
parenchymal, unlike the lesions shown in the case illustrated,
making metastases an unlikely diagnosis.
DIAGNOSIS: Germinoma.
KEY FACTS
CLINICAL
• Germ cell tumors (GCTs) are an important category
of pediatric brain tumors . However, it should be
remembered that the vast majority of GCTs occur in
an extracranial site and do not involve the central nervous
system.
• Intracranial GCTs typically present in the second
( 70%) or third decades, possibly due to increased
gonadotropin secretion during puberty. Symptoms
depend on tumor location: Suprasellar GCTs typically
present with neuroendocrine dysfunction, visual symptoms,
or headache; pineal region GCTs present with
features of elevated intracranial pressure or Parinaud's
syndrome ( failure of upward gaze and retractory nystagmus).
The increased thirst and urination of the
patient shown above was due to diabetes insipidus
related to the suprasellar lesion.
• Two major forms of GCTs are recognized: germinomas
and nongerminomatous GCTs. Germinomas are
the least malignant type of GCTs. The spectrum of
nongerminomatous GCTs includes embryonal carcinoma,
endodermal sinus tumor, benign or malignant
teratomas, and choriocarcinoma, all of which are more
malignant than germinomas.
• GCTs account for 1% to 3% of pediatric brain tumors
in the Western hemisphere, but they are reported to
be more common in Japan, where they comprise 5%
to 1 5% .
• Ninety-five percent o f intracranial GCTs are located i n
the midline, along a n axis from the suprasellar cistern
to the pineal gland. About 55% solely involve the
pineal region, 35% involve the suprasellar region, and
about 5% involve both locations.
• About 70% of GCTs in the suprasellar region are germinomas.
Conversely, 65% of GCTs in the pineal
region are of the nongerminomatous type.
• Pineal region GCTs do not arise from the pineal gland
itself but from rests of embryonic germ cells.
• Suprasellar GCTs are equally frequent in males and
females, but the ratio of males to females with pineal
GCTs is about 1 0 to l .
• Germinomas are very radiosensitive tumors, usually
rapidly shrinking within a few months of beginning
radiation therapy. Nongerminomatolls GeTs respond
poorly to radiotherapy but are sometimes sensitive to
chemotherapy.
295
• Overall prognosis for GCTs depends on patient age,
tumor type, and tumor location. Patients < 1 5 years at
the time of diagnosis have a better 1 0 -year survival rate
(90%) than older patients ( 50%) . The prognosis for
suprasellar germinomas (90% survival at 1 0 years) is
much better than for pineal germinomas. Prognosis for
nongerminomatous GCTs, on the other hand, is generally
poor, with about a 50% I -year survival rate .

Front 143

Two patients with the same diagnosis are presented. The patient in Figure 6-4A
was noted to have seven cutaneous cafe-au-Iait spots. The patient in Figure 6-4B
has radicular pain along the course of the left second rib.

Back 143

Spinal dural ectasia in the setting of neurofibromatosis:
This could be a consideration in Figure 6-4A
as the cause of dilation of the thecal sac and nerve root
sleeves. However, the dilated nerve root sleeves would
be expected to be filled by contrast material or CSF,
rather than by soft-tissue masses, making this an incorrect
diagnosis.
• Meningioma: Tlus is a possible consideration in
Figure 6-4A because, on occasion, meningiomas can
extend through the neural foramen. However, a nerve
sheath tumor is more common and more Likely to
cause the "dumbbell" configuration seen in this case.
• Drop metastases: Solitary CSF metastases along the
proximal nerve root can be seen occasionally but are
rare. In the absence of any other Likely cause, this consideration
could be essentially excluded by imaging the
remainder of the CNS.
• Plexiform neurofibromas: These tumors appear as
multiple, tortuous, worm-like masses arising along the
axis of a major nerve, unlike the solitary, smoothly
marginated masses seen in these cases, making this an
unlikely diagnosis.
• Nerve sheath tumor: These lesions are typically
smoothly contoured masses that can assume a dumbbell
configuration (like the appearance in Figure 6-4B ) .
They densely enhance after contrast administration.
These features make tlus diagnosis the most likely.
+ DIAGNOSIS: Nerve sheath tumor.
+ KEY FACTS
CLINICAL
• Schwannoma, neurinoma, and neurilemmoma are synonymous
terms used to refer to Schwann cell tumors.
• Schwannomas and neurofibromas are collectively
referred to as nerve sheath tumors but are different
pathologic entities.
• Nerve root schwannomas do not encase the adjacent
nerve root, usually involve tlle dorsal (sensory) root,
are usually solitary, and are not associated with neurofibromatosis.
In contrast, neurofibromas encase the
dorsal nerve root, are usually multiple, and are frequently
associated with neurofibromatosis, even when
solitary.
• Nerve sheath tumors are often associated witll radicular
pain or motor dysfunction related to a specific
nerve root.
• Nerve sheath tumors are found most frequently in the
cervical region and usually located in the extramedullary
intradural compartment ( about 60% of
cases) , but they are extradural in 25% of cases, and
both extra- and intradural ( in which case they often
assume a dumbbell configuration ) in 1 5% of cases.
Rarely, these tumors can be intramedullary.
297
• Nerve sheath tumors can undergo malignant degeneration
(seen in 5% to 1 0% of cases) , usually after a
latency period of 10 to 20 years. Thus, malignant
degeneration would typically be seen in the third or
fourth decade of Life .
RADIOLOGIC
• From an imaging standpoint, schwannomas and neurofibromas
resemble one another very closely.
Furthermore, distinction of the two entities on imaging
studies is not an important issue. For these reasons,
they are generally reported on imaging studies
simply as nerve sheath tumors.
• One feature that can occasionally be used to distinguish
schwannomas from neurofibromas is the asymmetric
location of schwannomas. Because schwannomas arise
from one side of the nerve root, they displace and
efface the normal nerve. They appear lobulated and
eccentric, whereas neurofibromas typically have a
fusiform shape.
• Nerve sheath tumors generally cause widening of the
neural foranlina. They can be associated with posterior
scalloping of the vertebral bodies in neurofibromatosis
due to dural ectasia.
• Nerve sheath tumors can have increased signal on T 1 -
weighted images (probably related to mucopolysaccharide
content) and dense contrast enhancement. Usually
markedly increased signal is seen on T2-weighted images
(due to high water content) . Many neurofibromas have
central areas of low signal on T2-weighted images.
• Differential diagnosis of benign versus malignant: On
CT and MRl, malignant nerve sheath tumors usually
have irregular, infiltrative margins, whereas benign
nerve sheath tumors usually have smooth margins. In
addition, malignant nerve sheath

Front 144

A 2 1 -year-old woman with occipital headaches. She has previously undergone suboccipital
decompression surgery and C 1 laminectomy.

Back 144

Chiari I malformation: In this congenital malformation,
herniation of the cerebellar tonsils occurs
through the foramen magnum. The abnormality
within the spinal cord is isointense to spinal fluid on all
pulse sequences and is due to syringohydromyelia,
which is commonly seen in patients with Chiari I malformation.
These findings make Chiari I malformation
the most likely diagnosis.
• Chiari II: This entity might be considered because of
the herniation of cerebellar tissue. However, other
manifestations of Chiari II-e.g., medullary kinking,
tectal beaking, a towering cerebellum, hydrocephalus,
and myelomeningocele-are not present.
• Chiari III malformation: In this malformation, herniation
of the hindbrain into a low occipital or high
cervical encephalocele is seen, often in association with
aplasia of the posterior elements of the three highest
cervical vertebral bodies. The absence of any of these
features excludes this diagnosis in the case shown .
• Other causes of cerebellar tonsillar herniation: A
posterior fossa mass can cause downward herniation of
the cerebellar tonsils. Developmental disorders involving
the craniovertebral junction (e.g., basilar impression
or cranial settling) due to a variety of conditions
(e.g., Paget's disease and rheumatoid arthritis) can
cause an abnormal relationship of the cerebellar tonsils
to the foramen magnum. None of these conditions is
present in the case shown.
+ DIAGNOSIS: Chiari I malformation.
+ KEY FACTS
CLINICAL
• Congenital hindbrain dysgenesis characterized by
downward herniation of the cerebellar tonsils was
described in 1 8 9 1 by Hans Chiari. In Chiari I malformation,
there is downward herniation of the cerebellar
tonsils into the spinal canal, with the fourth ventricle
and vermis remaining in a relatively normal position,
except in severe cases.
• This malformation is thought to result from a dysplasia
of bone at the craniocervical junction.
• Patients with Chiari I malformation typically are first
diagnosed in young adulthood. Almost all symptomatic
patients have at least 5 mm of cerebellar herniation.
• Symptoms and signs can be on the basis of either
compression of the cervicomedullary junction or
syringohydromyelia.
• The most common clinical features are hypesthesia
(decreased sensation) and weakness in the extremities
(about 50%), headaches, cranial neuropathy, and long
tract findings (e.g., gait disturbance, spasticity, and
bowel and bladder dysfunction ) .
• Treatment i s usually directed a t decompression o f the
cervicomedullary junction and consists of suboccipital
decompression of the foramen magnum with cervical
299
laminectomy to the level of the tonsillar herniation .
Some surgeons will place a shunt tube through the
foramen of Magendie into the fourth ventricle. I n
addition, treatment o f syringohydromyelia can b e performed
by decompression and, on occasion, shunting.
RADIOLOGIC
• The diagnosis is made by measuring the displacement
of the tonsils below a line from the basion (anterior lip
of foramen magnum) to the opisthion (posterior lip of
the foramen magnum ) . The normal position of the
tonsils varies with age. Tonsillar herniation is present
when the tonsils are ..6 mm ( .. 1 0 years), 5 mm (age
1 1 to 30), or 4 mm ( age 3 1 to 80) below this line .
Most patients present in late childhood or early adulthood-
hence, the usual criterion of 5 mm. The tonsils
are considered low lying rather than herniated when 3
to 5 mm of inferior displacement is present.
• The peg-like configuration of the tonsils narrows the
posterior CSF space at the level of the foramen magnum,
altering the CSF flow dynamics. This may be
shown by cine MR flow techniques.
• Hydrocephalus is seen in 2 0% to 25% of Chiari I malformation
patients.
• Compression of the brain stem and upper cervical cord
may be an important cause of symptoms. Arachnoid
adhesions may develop due to repeated trauma of the
cerebellum, further compromising CSF flow.
_. Syringohydromyelia occurs in 60% to 70% of patients,
usually in symptomatic patients. This condition is more
appropriately termed hydromyelia because the CSF-filled
cavity develops in the ependyma-lined central canal. The
most accepted theory of causation of syringohydromyelia
is transmission of exaggerated CSF pulsations (due to
restricted flow at the level of the fourth ventricle outlet
foramina) into the central cavity of the spinal cord.
• Basilar invagination-i. e . , extension of the tip of the
odontoid process >5 mm above Chamberlain's line (a
line drawn from the posterior margin of tlle hard palate
to the posterior aspect of the foramen magnum )-is
seen in about 25% of Chiari I malformation patients.
• Skeletal anomalies are common in Chiari I malformation
and include assimilation of Cl to the occiput
( 1 0%), partial nonsegmentation of C2 and C3 ( 1 5%),
and KLippel-Feil deformity ( 5% ) .

Front 145

A 1 6-year-old boy with left proptosis, chemosis, decreased visual acuity, and a bruit
heard over the left orbit.

Back 145

Orbital pseudotumor: This diagnosis would not
account for a number of features in the case showne.
g., orbital bruit, dilatation of the superior ophthalmic
vein (SOV), and abnormal commwlication between
the internal carotid artery ( I CA) and SOv. This diagnosis,
therefore, is unlikely.
• Thyroid orbitopathy ( Graves' disease): This diagnosis
might be considered because of the proptosis and
extraocular muscle enlargement. However, involvement
of both orbits is typical, and patients are usually
much older than in the case presented. Furthermore,
Graves' disease would not accow1t for some of the
MRI findings (e.g., dilatation of the left cavernous
sinus and SOV) or the angiographic findings.
• Optic nerve plexiform neurofibroma: Enlargement
of the orbital or retro-orbital segments of the optic
nerve would be expected but are not present in the
case shown. Again, an orbital bruit, dilatation of the
SOV, and the angiographic findings would not be
expected.
• Carotid-cavernous fistula (CCF): Patients with this
diagnosis typically present with orbital pain, proptosis,
and a bruit. Imaging findings can include dilation of
the SOV and widening of the cavernous sinus. This is
the correct diagnosis.
+ DIAGNOSIS: Carotid-cavernous fistula.
KEY FACTS
CLINICAL
• Clinical features of CCF depend on the predominant
route of venous drainage. When the majority of the
venous drainage is into the superior and inferior ophthalmic
veins, ocular chemosis, proptosis (secondary to
venous congestion ), glaucoma, and occasionally, unilateral
visual loss are found. When the bulk of the
venous drainage is into the superior, inferior, and petrosal
sinuses, or when the cavernous sinus becomes
greatly distended, a cavernous sinus syndrome consisting
of ophthalmoplegia and facial pain occurs.
• In traumatic CCFs, a delay in symptom onset of days
or weeks after tlle injury is common.
• CCFs are best classified by the nature of the arteriovenous
connection, which is eitller direct or indirect.
• Direct CCFs are due to a direct connection between
the internal carotid artery ( ICA) and the veins of the
cavernous sinus. Etiologies include ( 1 ) trauma,
( 2 ) rupture of an intracavernous ICA aneurysm, and
( 3 ) a fistulous communication due to an underlying
vasculopathy (e.g., Ehlers-Danlos syndrome) .
• Traumatic CCFs frequently follow skull base fracture
or penetrating injuries but can be iatrogenic (e.g., after
surgery at sites near the cavernous sinus, such as sphe-
301
noidotomy or trigeminal rhizotomy). These lesions are
often high-flow conduits between the arterial and
venous circulation.
• Indirect CCFs are typically spontaneous and caused by
development of multiple fistulous commwucations
between dural branches of the carotid circulation and the
cavernous sinus. The volume of blood shunted in indirect
CCFs is usually much smaller tllaJl in direct CCFs.
• CCFs sometimes involve both cavernous sinuses (and
hence both orbits) because commillUcation between the
cavernous sinuses is allowed by the circular sinus, the collective
term for the anterior aJld posterior intercavernous
sinuses that variably connect both cavernous sinuses.
• Conservative treatment of patients Witll indirect CCFs
and n1ild symptoms is often attempted by frequent,
self-administered external compression of the carotid
artery and jugular vein for many nUnutes at a time.
However, most patients need invasive treatment.
• Complications requiring emergency treatment are:
( 1 ) rapid progression of proptosis or visual loss, and
( 2 ) development of increased intracranial pressure
( due to cortical venous hypertension, caused by
diversion of blood flow into cortical veins) and intraparenchymal
or subarachnoid hemorrhage ( following
rupture of a large cavernous sinus varix or congested
cortical vein ) .
RADIOLOGIC
• Major findings on CT and MRI include extraocular
muscle enlargement, proptosis, and dilation of the ipsilateral
cavernous sinus and SOv.
• Reversal of flow through the SOV can be shown on
phase-contrast MR angiography.
• The site of the fistula and exact arterial supply can only
be shown by catlleter angiography. This information is
important for planning endovascular therapy. Findings
include early opacification of the cavernous sinus, poor
opacification of the rCA distal to the fistula, aJld retrograde
filling of dilated venous tributaries.
• Endovascular therapy with preservation of distal rCA
flow is the standard first-line therapy. Detachable balloons
or, on occasion, coils are used for large-hole fistulas
( e .g., direct CCFs ) . Embolic agents such as
isobutyl-2-cyanoacrylate or polyvinyl-alcohol particles
are used for indirect CCFs. Surgery is reserved for
cases that fail endovascular tllerapy.

Front 146

A 65-year-old woman with mild proptosis.

Back 146

Orbital pseudotumor (idiopathic orbital myositis):
Myositis is one of many manifestations of orbital
pseudo tumor. This is an unlikely diagnosis for the case
shown above because diffuse enlargement of the entire
extraocular muscle is usually seen in orbital pseudotumor,
whereas the tendinous portions of the muscles
are not enlarged in Figure 6-7 A .
• Neoplasm arising from muscle: Tumors such a s rhabdomyosarcoma,
lymphoma, leukemia, and metastases
can involve the extraocular muscles. However, bilateral,
symmetric involvement makes this diagnosis unlikely.
• Vascular congestion causing extraocular muscle
enlargement: Muscle enlargement can result from vascular
congestion associated with high blood-flow states
such as carotid -cavernous fistula (see Case 6 ) . This
condition is often manifested clinically by chemosis
and an orbital bruit ( neither of which was present in
this patient) and radiologic findings of dilatation and
tortuosity of the superior ophthalmic vein (which is of
normal size in this patient) . This diagnosis is, therefore,
unlikely.
• Graves' ophthalmopathy: This is the best diagnosis
given the bilateral muscle enlargement, predominant
involvement of the inferior, medial, and superior rectus
muscles, and sparing of muscle tendons.
+DIAGNOSIS: Graves' disease (thyroid ophthalmopathy).
+ KEY FACTS
CLINICAL
• Thyroid ophthalmopathy is a common cause of unilateral
or bilateral proptosis in adults.
• Extraocular muscle enlargement occurs due to lymphocytic
and plasmacytic infiltration of connective tissue
(presumed to be autoimmune in origin) accompanied
by mucopolysaccharide deposition, edema, and fibrosis.
• Enlargement of the extraocular muscles can produce
proptosis, decreased range of globe motion and
diplopia, and periorbital and conjunctional edema due
to elevated orbital pressure.
• Visual loss is threatened in 1 0% of patients due to compressive
optic neuropathy ( caused by compression of the
303
optic nerve at the orbital apex due to muscle enlargement)
or corneal ulceration ( due to corneal exposure
secondary to lid retraction and exophthalmos) .
• Thyroid ophthalmopathy usually occurs i n patients
with hyperthyroidism, but 1 0% of patients have no
clinical or laboratory evidence of thyroid disease.
• Treatment is typically with corticosteroids. Occasionally,
radiation therapy or surgical decompression
of the optic nerve is performed is cases in which
vision is threatened.
RADIOLOGIC
• Thyroid ophthalmopathy typically produces enlargement
of the bellies of the extraocular muscles, with
sparing of the tendinous insertions, which can be helpful
in distinguishing it from other causes of extraocular
muscle enlargement.
• The inferior rectus muscles and medial rectus are
affected earliest and most severely. The lateral rectus
muscle is usually the least involved. In 6% of cases,
only one muscle is enlarged.
• Approximately 85% of cases have bilateral disease on
CT or M R! .
• Imaging in the coronal o r sagittal plane i s better suited
for determination of enlargement of the extraocular
muscles, particularly the inferior rectus and superior rectus
muscles (which are cut tangentially on axial images).
• Findings other than extraocular muscle enlargement
that may be seen include an increase in the volume of
orbital fat and enlargement or anterior displacement of
the lacrimal gland.

Front 147

A 6-year-old girl with short stature and diabetes insipidus.
FIGURE 6-

Back 147

Chiasmatic/hypothalamic glioma: These lesions usually
spare the sella and are usually not cystic or calcified.
• Craniopharyngioma: These lesions account for 50%
of suprasellar tumors in children. A typical MR appearance
is that of a heterogeneously enhancing, calcified
sellar and suprasellar mass with multilobulated cystic
components, as in this case. This is the best diagnosis
for the lesions shown.
• Germ cell tumor (GCT): The age of these patients
and lesion location make this category of tumor
(which includes a wide number of lesions; see Case 3 )
a possible consideration. However, germinomas typically
have homogeneous signal intensity. Cystic components
are occasionally seen but are not usually large.
Teratomas have heterogeneous signal like the lesion
shown here, but they usually have fat and calcium and
are not typically cystic. These factors make GCT an
unlikely diagnosis for the cases shown above.
• Pituitary adenoma: These lesions are very uncommon
in children and, unlike the lesions shown here,
do not usually have large cystic components and are
not calcified.
• Rathke's cleft cyst: These lesions often contain mucoid
material that is hyperintense on all pulse sequences.
However, they are typically intrasellar (unlike the lesion
shown above, which is predominantly suprasellar), usually
much smaller than the lesion shown here, are not
calcified, and do not contrast-enhance.
+ DIAGNOSIS: Craniopharyngioma.
+ KBY FACTS
CLINICAL
• Craniopharyngiomas are derived from squamous
epithelial remnants of Rathke's cleft. Most involve
both the sellar and suprasellar regions, but less commonly,
they can be located solely within the sella or
tlle third ventricle.
• These tumors represent 3% to 5% of all intracranial
tumors, show no gender predilection, and have a
bimodal age distribution. More than half occur in
childhood (peak: ages 5 to W years) and adolescence,
but a second peak is seen in middle age.
• About 90% of craniopharyngiomas are partially cystic.
Rarely, the lesion is purely cystic. The cyst contents
consist of straw-colored or oily brownish fluid with
variable amounts of cholesterol crystals.
• Clinical symptoms are typically due to mass effect on
adjacent su·uctures-e .g., visual field defects due to
compression of the optic pathways and neuroendocrine
dysfunction due to compression of the hypothalamus
and pituitary gland.
• Two distinct clinicopathologic variants are recognized.
The adamantinomatous type is the more common of
the two variants. It can be seen in both adults and
children but is more common in the latter. The papil-
305
lary form almost always occurs in adults, accounting
for about one-third of adult craniopharyngiomas. It is
more often soLid, less frequently calcified, and has been
reported to have a better surgical outcome than
adamantinoma to us tumors in the adult.
• Presenting symptoms and signs are usually those associated
with increased intracranial pressure ( headache,
nausea, vomiting, papilledema) or visual disturbance.
Craniopharyngiomas are hormonally inactive and can
compress the pituitary gland and hypothalamus, causing
neuroendocrine dysfunction.
• There is considerable debate regarding the best management
of craniopharyngiomas-i.e., whether to use
surgical resection or cyst aspiration followed by radiation
tllerapy. Surgical excision is complicated by the fact
that complete resection of the tumor away from the
hypothalamus and pituitary stalk is often impossible.
RADIOLOGIC
• Calcifications are frequently present. CT is more sensitive
than MRI in detection of these calcifications.
• The noncontrast CT appearance is that of an inllomogeneous
mass that frequently has cystic components and
punctate or clumpy calcifications. Occasionally, the cyst is
hyperdense, thought to be due to very high protein concentration.
Variable degrees of a soft-tissue component
can be seen, which enhance after contrast administration.
On CT and MRI studies, when cyst contents are identical
in appearance to cerebrospinal fluid, the presence of
calcifications and soft-tissue components helps to distinguish
craniopharyngioma from arachnoid cyst, a lesion
that also commonly occurs in the suprasellar region.
• The cystic components of craniopharyngiomas are
variable on T l -weighted MRIs, varying from isointensity
with CSF to hyperintensity. The hyperintense
signal has been attributed to very high protein concentrations,
although the presence of cholesterol crystals
and triglycerides has also been suggested. Solid
portions are frequently relatively isointense to brain
on all pulse sequences.
• MRI is helpful in preoperative definition of the relationship
of the tumor to the optic nerves and chiasm,
internal carotid arteries and tlleir branches, pituitary
stalk, hypothalamus, and tl1ird ventricle.
• The papillary type has a more uniform CT and M R
appearance with less frequent calcification and cyst
formation.

Front 148

A 38-year-old man with spastic paraparesis. He experienced an episode of right
facial paralysis of 2 weeks' duration 3 years earlier.

Back 148

Diffuse axonal injury: This entity is seen as one or
more hyperintense foci on T2 -weighted images, but it
is found following trauma, which was not present in
this patient. Furthermore, a more random clistribution
of the cranial lesions, rather than an alignment at right
angles to the ventricles, would be expected.
• White matter lesions associated with aging:
Hyperintense foci can be seen as ( usually incidental)
finclings in middle-aged and elderly patients. Although
occasional foci can be seen in young patients, they are
usually small, few in number, and confined to the
brain, making this an incorrect cliagnosis.
• Vasculitis: Scattered white matter hyperintense lesions
are often seen in patients with vasculitis due to small
infarcts. Central nervous system vasculitis is usually
characterized by a relatively acute or subacute onset
over the course of weeks or months. The history of
repeated neurologic events occurring over the course
of a few years makes this cliagnosis unlikely.
• Multiple sclerosis (MS): MS typically produces multiple
white matter lesions that are hyperintense on T2-
weighted images. Characteristically, the lesions are
aligned at right angles to the ventricular surface, as in
the case shown above. Contrast enhancement is relatively
commonly seen.
• Neurosarcoidosis: This clisease generally affects leptomeninges
but can produce lesions within the white
matter and, on occasion, the spinal cord. It can have
the same appearance on MRI as MS. The presence of
systemic sarcoidosis (e.g., bilateral hilar lymphadenopathy,
elevated angiotensin -converting enzyme levels),
not mentioned as present in this patient, would be
considered evidence that the central nervous system
lesions are due to neurosarcocliosis.
DIAGNOSIS: Multiple sclerosis.
KEY FACTS
CLINICAL
• MS is a demyelinating clisease typified by a remitting/
relapsing course, with multiple exacerbations and
remissions involving clifferent parts of the central nervous
system. Thus, lesions are characterized by being
"multiple in space and time. "
• The most common sites o f involvement are the white
matter tracts of the centrum semiovale, corona racliata,
and brain stem.
• Spinal cord involvement is seen in about 1 0% of cases.
• Onset of symptoms is usually in the third to fifth
decades.
307
• Optic neuritis is common. Furthermore, a significant
proportion of patients with isolated optic neuritis later
are cliagnosed as having MS.
• The prevalence of MS is higher at northern and temperate
climates compared to regions near the equator.
• Laboratory abnormalities include the presence of
oligoclonal bands in cerebrospinal and abnormal electrophysiologic
stuclies (i.e., visual, auclitory, or
somatosensory evoked potentials) .
• The exact etiology i s w"lknown, but M S i s generally
considered an autoimmune phenomenon.
RADIOLOGIC
• MS lesions are typically periventricular in location.
Although many cliseases can produce such lesions, MS
plaques are often oval and have a perpenclicular orientation
to the lateral ventricles.
• MS plaques are generally much more obvious on MRI
than CT.
• Lesions are characteristically hyperintense on T2-
weighted images. Long TR/short TE ( "proton density"
weighted ) images are most sensitive for detecting
small lesions adjacent to ventricular surface because
they are hyperintense relative to cerebrospinal fluid on
this pulse sequence.
• MS plaques are generally either isointense ( most commonly)
or hypointense compared to white matter on
T 1 -weighted images.
• Lesions in the corpus callosum, middle cerebellar
peduncle, or spinal cord increase the likelihood of the
diagnosis of MS.
• Optic nerve plaques can be seen using contrastenhanced
T 1 -weighted or T2-weighted images using
fat saturation technique to climinish background signal
from orbital fat.
• Contrast-enhancing lesions are relatively frequently
seen and are generally considered to represent plaques
in the acute ( "active" ) stage of demyelination.

Front 149

A 20-year-old man with a primary brain tumor.

Back 149

Leptomeningeal ("drop") metastases: This term
refers to leptomeningeal spread of tumor arising from a
primary central nervous system ( CNS) neoplasm. Small
metastases disseminate through the cerebrospinal spaces
and subsequently enlarge. The diffuse pattern of
enhancing nodules along tlle entire length of me cauda
equina in a patient with a known primary brain tumor
makes mis diagnosis me most likely consideration.
• Neurofibroma of the spinal roots: This diagnosis is
considered because neurofibromas usually contrastenhance.
However, mey are usually larger and oriented
along me axis of me nerve root.
• Granulomatous disease: Granulomatous diseasese.
g., sarcoidosis-can coat me spinal cord and spinal
nerve roots. The appearance is usually tllat of contrastenhancing
nodules accompanied by adjacent enhancement
of me pia and arachnoid (not present in me case
shown above ) . Granulomatous involvement at omer
cranial sites ( e.g., me basilar meninges) or extra-CNS
sites (e.g., me lungs) might be expected, which is not
reported in this patient.
• Contrast enhancement of spinal cord vessels:
Contrast enhancement of veins posterior to tlle spinal
cord is ofren seen on MRI, even in normal subjects.
On a single axial image, contrast enhancement witlun
veins can be mistaken for enhancing metastases. The
distinction between me two entities can be made by
looking at serial axial images. Because veins are generally
oriented along tlle craniocaudad axis, venous
enhancement should be seen in me same site on serial
axial in1ages; metastases will be seen on only one or
two of a series of axial images. The lesions shown
above are not oriented along me spinal cord and do
not represent enhancing vessels.
DIAGNOSIS: Drop metastases.
KEY FACTS
CLINICAL
• Between 5% and 30% of children wim CNS tumors will
have cerebrospinal fluid (CSF) metastasis at tlle time of
diagnosis or at some point in me clinical course-i.e.,
at initial diagnosis or at time of recurrence.
• Clinical status is not a good predictor of me presence
of drop metastases. Unless CSF metastases are quite
large, patients wim drop metastases are generally
asymptomatic and appear well.
• Detection of drop metastases is vital, because survival
is poor if early treatment of tumor dissemination is not
performed.
309
• Imaging studies are frequently positive for drop metastases
in patients in which cytologic examination of me
CSF is negative . However, CSF cytologic findings are
positive in 30% of cases in which imaging studies are
negative. Therefore, CSF examination and imaging
studies are complementary-eitller examination can be
positive when the other examination is negative .
• Medulloblastoma is tlle most common source of drop
metastasis (about 50% of all cases), followed by
glioblastoma ( about 1 5% ) .
• Two age peaks o f drop metastases are seen i n patients
Witll childhood brain tumors. The first peak occurs at
about age 6 years, at tlle time of initial diagnosis. The
second occurs at about age 1 5 years and occurs in two
conditions: ( 1 ) patients Witll an incompletely treated
brain tumor who have had previous prophylactic spinal
radiation but subsequently develop drop metastases,
and ( 2 ) patients Witll previous remission of brain
tumor who develop recurrence of me brain tumor
wim coexistent drop metastases.
• CSF cytology is still me most sensitive means for
determining leptomeningeal tumor spread, being positive
on initial lumbar puncture in about half of patients
wim proven CSF metastases.
RADIOLOGIC
• Drop metastases tend to be more frequent in me lower
spinal canal-i .e., tlle lumbosacral area ( 73%), probably
due to me effects of gravity.
• Metastases witlUn tlle spinal canal are usually dorsal in
location, reflecting CSF flow from me head; ventral
CSF flow tends to be toward me head.
• The sensitivity of contrast-enhanced MRI is greater man
CT myelography or myelography alone. Rapid screeIUng
of me entire spinal axis can be performed by MRI in a
nOIUnvasive malU1er. CT myelography is an invasive
study in which me myelogram is typically used to direct
CT imaging of only a portion of tlle spinal Callal .

Front 150

A 50-year-old woman with sudden onset of low back pain and progressive paraparesis
over 6 hours. Symptoms began suddenly after the patient sneezed.

Back 150

Epidural metastases: These usually arise from vertebral
body metastases and extend into the spinal canal,
making this an unlikely diagnosis. Nonetheless, in rare
instances, some metastases (e.g., lymphoma and
leukemia) can infiltrate solely the soft tissues and dura.
However, these diagnoses would be unlikely in light of
the acute onset of symptoms and the hypointense signal
of the lesion in the second patient shown above.
• Spinal epidural abscess: Risk factors include insulindependent
diabetes mellitus, cl1fonic renal failure, intravenous
drug abuse, or recent spinal surgery ( none of
which was present in this patient). Usually osteomyelitis
or discitis is present. However, in the patients shown
above, only the posterior epidural space is involved.
• Spinal epidural hematoma (SEH): The rapid onset
of neurologic deficit is consistent with this diagnosis.
The absence of trauma in the first patient discussed
above does not exclude SEH, because SEH sometimes
occurs after Valsalva maneuvers that accompany exertion
( e.g., weightlifting) or vigorous cough.ing or
sneezing ( as in this patient) . The inl10mogeneous, predominantly
hypointense signal on T2-weighted images
is compatible with acute hemorrhage and would be
unexpected with other entities.
• Spinal cord infarction: This entity is a consideration
based on the acute onset of neurologic findings in both
patients. However, infarction would be expected to
produce an intramedullary lesion, not an epidural lesion,
and motor and sensory dysfunction ratl1er than pain.
DIAGNOSIS: Spinal epidural hematoma.
KEY FACTS
CLINICAL
• SEH can occur spontaneously or after various degrees
of spinal trauma, including minimal trauma, stretching
or twisting of the vertebral column without vertebral
fracture, Valsalva maneuvers ( the first patient shown
above ), or spinal procedures ( e . g . , following lumbar
puncture, which was the precipitating event in the second
patient discussed above ) .
• The typical clinical presentation is acute onset o f back
pain and rapid development of myeiopatl1Y inferior to
the level of the hematoma. Early diagnosis of SEH is
critical because the likelihood of reversal of neurologic
deficit is related to duration of symptoms.
• SEH can be seen at any age. About half of cases occur
in patients >50 years. It is slightly more common in
men. The two most common sites are the low cervical
level and the tl10racolumbar junction.
• Emergency laminectomy to evacuate the hematoma is
usually performed. Preoperative radiologic demonstra-
311
tion of tl1e extent of the hematoma is important for
surgical planning.
• In most patients, the etiology of SEH is not known,
even after surgery. Possible etiologies include a weakened
spinal epidural vein (e.g., ruptured during
Valsalva maneuver), spinal arterial hemorrhage, and
rupture of a small arteriovenous malformation.
RADIOLOGIC
• SEHs are typically fusiform in shape, witl1 tl1eir longest
din1ension along the craniocaudad axis. They are best
seen on sagittal MRI .
• These lesions are usually located i n the posterior
epidural space and are typically Wee to four vertebral
bodies in length.
• MRI is the most sensitive and specific means of making
the diagnosis, but tl1e diagnosis can also be made by
CT alone, myelography alone, and CT myelography.
• The MR signal intensity of SEH depends on the age of
the hemorrhage. I n the acute stage ( i . e . , that of intracellular
deoxyhemoglobin ) , the SEH is hypointense on
T2 -weighted images. After a few days, SEH becomes
hyperintense on T l -weighted images.
• If MRI is unavailable or contraindicated, CT myelography
is an acceptable means of making the diagnosis.
On axial images, tl1e lesion is seen as a ( usually posterior)
epidural mass that is isodense or hyperdense to
spinal cord and displaces fie fiecal sac or spinal cord.
• Myelographic findings are nonspecific and consist of
narrowing or block of the intratl1ecal contrast column.
The lesion can often be seen to be smootllly tapered at
each end.
• The diagnosis can be difficult to make by plain CT when
the epidural mass is isodense to the spinal cord.
• SEH can be difficult to distinguish from spinal subdural
hematoma, a very uncommon entity. The distinction
is usually not important, because surgical
evacuation is usually performed in botl1 cases. On axial
CT and MRI , subdural hematoma is frequently crescentic
and sometimes separated from fie lamina by
epidural fat. On MRI, subdural hematoma can sometimes
be seen to be separated from tl1e epidural fat by
the linear hypointense signal of fie dura.

Front 151

A 30-year-old woman with progressively worsening headaches.

Back 151

Meningioma: This tumor might be a consideration
because meningiomas are commonly calcified, like the
lesion shown. However, meningiomas are extra-axial
lesions, whereas the lesion shown is intra-axial.
• Tumor with previous radiation therapy: It is common
for tumors that have undergone radiation therapy
to become calcified. However, a history of radiation
therapy is not present in the case shown above.
• Oligodendroglioma: This diagnosis should be considered
because the lesion shown above is heavily calcified.
In particular, it is unusual for any tumor other
than oligodendroglioma to develop calcification of this
degree in the absence of prior radiation therapy.
• DIAGNOSIS: Oligodendroglioma.
+ KEY FACTS
CLINICAL
• Oligodendrogliomas are tumors that arise from oligodendrocytes,
the cells from which central nervous system
myelin forms.
• These tumors account for 5% to 1 0% of intracranial
gliomas.
• A 2 to 1 male predominance is seen. The peak age is
in the fourth and fifth decades.
• Slightly more than half of oligodendrogliomas occur in
tl1e frontal lobes, and another 1 5 % each in tl1e temporal
lobes and parietal lobes.
• Oligodendrogliomas most frequently occur in the
periphery of the brain and involve brain cortex
(accounting for the high prevalence of seizures) .
However, as i n the cases shown above, i t i s not
uncommon for lesions to occur centrally.
• Seizures are tl1e most common presenting feature.
• These tumors are characteristically slow growing and
can on occasion erode overlying skull. Perinunoral
edema is mild or absent. Nodular calcification is the
hallmark, seen in 70% to 90% of cases.
313
• About 50% of oligodendrogliomas have a mixed histology
consisting of astrocytoma and anaplastic oligodendroglioma.
These tumors have a poorer prognosis than
the remainder of oligodendrogliomas.
RADIOLOGIC
• Between 80% and 90% of oligodendrogliomas are calcified.
About two-thirds of oligodendrogliomas have a
focus of calcification > 1 cm.
• The CT scan appearance is that of an inhomogeneous
hypodense mass that typically has dense nodular calcification
. The tumor frequently extends to involve cortex
and can erode tl1e adjacent calvarium.
• Intratumoral cysts are common. Intratumoral hemorrhage
can occasionally be seen.
• Overall, about one-third of oligodendrogliomas contrastenhance,
although it is usually mild. However, two-tlurds
of oligodendrogliomas witl1 a histologic grade of I I I or
IV contrast-enhance, often in a ring fashion.
• MRI is less sensitive than CT in detecting tumor calcification
but is superior in defining tumor extent.
• MR scans show mixed hypo- and isointense areas on
T l -weighted images and hyperintense foci on T2-
weighted images. Regions of calcification can be seen as
hyperintense foci on T 1 -weighted images and
hypointense foci on T2-weighted images. As on CT,
contrast enhancement is typically very nlild. Dense contrast
enhancement suggests an anaplastic component.

Front 152

A 17 -year-old girl with slow onset of mild spastic paraparesis and urinary incontinence.

Back 152

Tightened mum terminale syndrome: In tlus syndrome,
the conus medullaris is normal or near-normal
in position, but clinical fe atures of spastic paraparesis
are present. These findings are solely due to the presence
of a filum tern'linale that is tlUckened (�.3 mm),
stretched, and under tension. As a result, the filum terminale
often has a curved course, projecting along tl1e
posterior aspect of the spinal cord ("bowstring appearanc
e"). However, in the case shown above, other
abnormalities are present: the conus medullaris is
markedly lower in position than normal, and the
FIGURE 6-13B oncontrast axial Tl-weighted image at the level
of the 51 vertebral body shows the thecal sac is widened and projects
outside the expected confines of the spinal canal. Instead of a normal
cauda equina, the neu ral elementS are arranged as a flat structure
(neural placode) abutting the surface of the hyperintense mass.
neural elements have an abnormal appearance (the flat
neural structure indicative of a neural placode) .
• Leptomeningeal ("drop") metastasis: This entity
might be considered because of the clinical fe atures
and the presence of a mass witlun the thecal sac.
However, tlUs entity occurs in the presence of a primary
brain tumor, which has almost always been diagnosed
prior to onset of spinal symptoms. Furthermore,
the mass in the caudal end of the thecal sac is hyperintense
on nonconttast Tl-weighted images and most
compatible with fa t rather than a neoplasm.
• Lipomyelomeningocele: In this disorder, dysraphism
of the lower lumbar and sacral posterior elements in
CASE #13 N euroradiology
association with a sac containing neural and fatty structures
and projecting beyond the confines of the spinal
canal is seen. These findings are present in the case
shown above. The hyperintense mass is a lipoma,
which has caused tethering of the spinal cord due to
adherence of neural elements to the lipoma. The flat
structure adherent to the Lipoma is the neural placode
often seen in this condition.
DIAGNOSIS: Tethered spinal cord due to a
lipomyelomeningocele.
KEY FACTS
CLINICAL
• There are three main congenital causes of spinal cord
tethering: ( 1 ) inu-adural lumbosacral lipoma, ( 2 ) tight
filum terminale, and ( 3 ) diastematomyelia (splitting of
the spinal cord with fixation due to a fibrocartilaginous
or osseous septum within the spinal canal) .
• Intraspinal lipomas causing spinal cord tethering can
be seen in the setting of: ( 1 ) a thickened filum terminale
that progressively widens into a lipoma, ( 2 ) a normally
formed conus medullaris adherent to an adjacent
lipoma, and ( 3 ) an incompletely closed conus
medullaris ( myeloschisis) attached to a lipoma.
• Presenting features of tethered cord can incl ude ( 1 ) pain
in the back, legs, buttocks, or perineum; ( 2 ) spastic
paraparesis (i.e., abnormal gait, leg weakness and muscular
atrophy, hyperreflexia, and urinary or fecal retention
or incontinence); ( 3 ) sensory changes in the
distribution of the lumbosacral roots; (4) tightened
Achilles' tendon; ( 5 ) scoliosis; and (6) pes cavus deformity
of the foot.
• Clinical features related to a tethered spinal cord typically
begin in late childhood, adolescence, or early adulthood
but can be seen in early childhood or middle age.
• Tethered cords can be seen in association with a variety
of spinal lesions, most commonly a lipoma or lipomyelomeningocele
.
• Intraspinal lipomas are not invariably associated with
neurologic findings; only about half of subjects with
these lesions develop symptoms. In particular, small
lipomas within the thecal sac or within the filum tenninale
(sometimes termed a fibrolipoma) can be incidental
findings seen at autopsy (about 20% of individuals)
or on cross-sectional imaging studies.
• Tethered cord syndrome can also occur solely in the
presence of a tight, slightly tllickened filum terminale
("tightened filum" syndrome ) . When neurologic features
suggestive of tethered cord syndrome are seen in
the absence of other structural abnormalities on MID,
it is important to pay particular attention to the tllickness
and course of the filum terminale to exclude findings
indicative of a tightened filum terminale (see tile
section on Differential Diagnosis) .
315
• Symptoms related to a tetllered spinal cord can be precipitated
(or worsened) by many factors, including
increased tension on the spinal cord (e.g., during pregnancy
or following acute anterior flexion of the trunk),
increased crowding of intraspinal contents (e.g., disc
herniation ), and minor trauma.
• Standard treaunent for a tethered spinal cord is surgical
lmtetllering by release of tile spinal cord, spinal
nerve roots, or filum terminale from the lesion causing
tetllering (e.g., from a spinal lipoma), or sectioning of
tile filum terminale (in tile case of a tightened filum).
Intraoperatively, only sLight cephalad movement of the
spinal cord would be expected to be seen after untethering.
Therefore, little change in the position of the
conus medulLaris would be expected on follow-up
imaging studies.

Front 153

A 37-year-old man with mild right hemiparesis and headache.
FIGURE 6-

Back 153

Primary brain tumors: Primary brain tumors usually
have inhomogeneous contrast enhancement and a
more variegated appearance . However, lymphoma can
appear hyperdense relative to white matter on noncontrast
CT, thought to be due to a high nuclear to
cytoplasmic ratio. Central nervous system ( CNS) lymphoma
is frequently solitary ( as in the case shown
above ) , but multiple homogeneously enhancing lesions
( frequently abutting an ependymal surface) are also a
common appearance.
+ DIAGNOSIS: Primary lymphoma of the central
nervous system.
+ KEY FACTS
CLINICAL
• Primary CNS lymphoma accounts for about 1 % of all
primary brain tumors but is increasing in frequency as
a complication of acquired immunodeficiency disorder
(AIDS ) .
• The CNS does not have intrinsic lymphoid tissue, and the
cell of origin of primary CNS lymphoma is unknown.
• Essentially all primary CNS lymphoma is composed of
the non-Hodgkin's type.
• Unlike primary CNS lymphoma, CNS spread from systemic
lymphoma is usually leptomeningeal, or duralbased,
in location rather than parenchymal .
• Patients with non-AIDS-related primary CNS lymphoma
usually present in later life ( usually in the sixth
decade) and are therefore older than the typical patient
with AIDS-related lymphoma.
• In addition to AIDS patients, other immunocompromised
patients (e.g., organ transplant recipients and
patients with congenital immunodeficiency diseases)
are at risk for primary CNS lymphoma.
RADIOLOGIC
• Lesions due to primary CNS lymphoma are often located
in tlle white matter, corpus callosum, and basal ganglia.
In about half of cases, multiple lesions are present.
• Ependymal extension of peri ventricular lesions is a
common fmding and, when seen, should raise the
diagnosis of primary CNS lymphoma.
317
• Calcification and hemorrhage are rarely seen. In
non-AIDS-related primary CNS lymphoma, peri tumoral
edema is usually absent or only mild. However, in the
setting of AIDS, edema can sometimes be quite marked,
causing lesions to simulate those of toxoplasmosis.
• Lymphoma not related to AIDS is often a homogeneous
mass that is hyperdense relative to white matter
on noncontrast CT. It thus differs in appearance from
AIDS-related lymphoma, in which lesions are often
inhomogeneous with hypodense components. Primary
CNS lymphoma in the two populations also differs from
the standpoint of contrast enhancement: non-AIDS
lymphoma frequently contrast-enhances in a homogeneous
marmer, but AIDS-related lymphoma often has
inhomogeneous enhancement in a ring-fashion, another
feature causing it to simulate toxoplasmosis.
• Lymphoma, when located deep within tlle brain, is
usually isointense to gray matter on spin echo MR
sequences, a finding that is also seen in other hypercellular
small cell-type tumors. However, on occasion, the
lesions can be very hyperintense on T2-weighted images.
• Parenchymal brain metastases from systemic lymphoma
can be indistinguishable from primary CNS lymphoma,
but parenchymal metastases are rare in the
absence of leptomeningeal lesions.
• AIDS-related primary CNS lymphoma can closely simulate
toxoplasmosis. However, toxoplasmosis lesions
frequently have a peripheral hyperintense rim on T l weighted
MR images, which i s hypointense o n proton
density and T2-weighted images, a finding not generally
seen in lymphoma. Thallium SPECT scans have
shown usefulness in distinguishing the two entities,
because scans are negative in toxoplasmosis and positive
in lymphoma.
• If hemorrhage is present, tllis argues against lymphoma,
and it is frequently seen in toxoplasmosis.

Front 154

A 2 1 -year-old woman with seizures.

Back 154

Hemorrhagic contusion: Tllis diagnosis might be
considered because of the superficial location of the
lesion and the MR signal characteristics indicating
hemorrhage. However, there is no history of trauma.
• Hemorrhagic neoplasm: Most or all of the lesion has
signal characteristics compatible with hemorrhage . It is
unusual for intra tumoral hemorrhage to occupy the
entire volume of the tumor.
• Arteriovenous malformation (AVM): This lesion
might be considered because of the evidence of hemorrhage.
However, AVMs typically appear on MRl as a
conglomeration of flow-voids, rather than solely a
focus of hemorrhage.
• Embolic infarction: This entity nlight be considered
because embolic infarcts occur in the periphery of the
brain and are frequently hemorrhagic . However, the
reticulated appearance shown above would be unusual
for a hemorrhagic infarction because they usually have
homogeneous signal.
• Cavernous angioma: These lesions are associated with
seizures and typically appear as rounded, reticulated
regions of abnormal signal with internal foci of hemorrhage
surrounded by dark signal on T2-weighted
images due to hemosiderin deposition. This is the correct
diagnosis. The entity shown in Figure 6- 1 5C has
features typical of a venous angioma, with which cavernous
angiomas are associated.
• DIAGNOSIS: Cavernous angioma with an
associated venous angioma.
KEY FACTS
CLINICAL
• Cavernous angiomas consist of a cluster of enlarged
vascular channels lacking intervelling brain parenchyma.
Unlike cavernous angiomas, AVMs have a
nidus of abnormal vessels with well-defined feeding
arteries and drauling veins.
• Cavernous angiomas can be either sporadic or familial
in nature .
• Multiple angiomas are found in 1 0% to 1 5% of patients
with the sporadic variety and about 75% of tllose Witll
the familial form .
• Symptom onset is typically in young adulthood. The
most common clinical features are seizures (40% to
70% of patients) , headache, and, on occasion, sudden
onset of neurologic deficit.
• Cavernous angiomas, especially those located Ul the
posterior fossa, are often fOWld in association with
venous angiomas, wllich are bellign venous developmental
abnormalities.
• Histologic examination of these lesions shows a cluster
of thin-walled (often thrombosed and calcified) vascular
charmels that are not separated from one another
by brain tissue .
319
• The rate of hemorrhage of cavernous angiomas has
been deternlined to be between 0.25% and 0 . 70% per
person year of exposure.
• Symptomatic cavernous angiomas tlut are superficial
are often resected if they are not located in eloquent
brain tissue. Brain stem lesions that are not amenable
to excision can be treated by stereotactic radiosurgery.
RADIOLOGIC
• Cavernous angiomas are usually <2 cm in size but
occasionally can be larger, particularly when substantial
hemorrhage has occurred.
• These lesions are frequently found incidentally on MRl
or CT studies performed for umelated symptoms.
• These lesions are almost always occult on angiography,
although rarely a small vascular blush (without arterial
feeders or early draining veins) can be seen.
• On CT, these lesions can be seen as well circumscribed,
frequently hyperdense lesions that often have
one or more small foci of calcification due to previous
hemorrhage . Often, however, lesions are isodense with
brain, especially if they are small or have not undergone
hemorrhage .
• These lesions typically do not contrast-enhance to a
large degree on CT or MRl.
• Edema is typically not seen surrounding cavernous
angiomas unless they have recently undergone a substantial
amount of hemorrhage.
• Generally, cavernous angiomas are occult on catheter
angiography but can occasionally be seen as a region of
capillary blush or pooling of contrast material in the
venous phase.
• MRl is very helpful in confirming the diagnosis when
it is suspected on CT because it can show multiple
lesions (making the diagnosis more likely) and reveal
tlle typical hemosiderin halo around lesions.
• T2-weighted MRls and gradient-echo images are sensitive
to the magnetic susceptibility effect of chronic
blood products.
• On occasion, cavernous angiomas can be difficult to
distinguish from prin1ary or secondary brain tumors.
The presence of multiple lesions is helpful in excluding
a primary tumor. The presence of calcification on CT
or a characteristic hemosiderin rim on MRl (both features
not expected with metastases) is helpful in making
the distinction .

Front 155

A 3S-year-old woman with visual loss over the period of a few weeks and mild
diabetes insipidus over the course of a year

Back 155

Leptomeningeal carcinomatosis: This diagnosis is
unlikely in the absence of a prior history of a non-CNS
neoplasm. Furthermore, preferential involvement of the
cisternal spaces at the base of the brain would not be
expected.
• Viral meningitis: Leptomeningeal enhancement due
to viral meningitis is typically thin, unlike the relatively
thick contrast enhancement seen at the level of the
optic chiasm and third ventricle seen in the case shown
above. B acterial meningitis, another consideration in
the case shown above, can be seen to produce thick
leptomeningeal enhancement. However, neither bacterial
nor viral meningitis would be expected to produce
the preferential leptomeningeal involvement at the
base of the brain seen in the case shown above
inferred on the basis of known extra-CNS sarcoidosis or
directly obtained by biopsy of tlle leptomeninges or
brain, which was performed in the case shown above
and showed noncaseating granulomas.
+ DIAGNOSIS: Neurosarcoidosis.
+ KEY FACTS
CLINICAL
• Sarcoidosis is an idiopathic systemic disease characterized
by formation of noncaseating granulomas in multiple
organ systems. The disease usually affects young
adults in me mird or fourth decade of life, who usually
present clinically with insidious onset of malaise,
weight loss, and fatigue.
• Only about 5% of patients have CNS symptoms, but
25% of patients have findings of CNS involvement at
autopsy. CNS symptoms usually begin within the first
few years after onset of systemic disease. The predilection
of the disease to involve the midline structures at
the base of the brain is reflected by the symptom distribution
outlined below.
• Cranial neuropathy ( especially seventh nerve paresis) is
me most common neurologic manifestation, seen in
more than half of patients with CNS disease.
• Aseptic meningitis due to granulomatous infiltration of
the leptomeninges is seen in about 20% of patients
with neurologic disease.
• Neuroendocrinologic dysfunction due to infiltration of
the hypothalamus or pituitary gland and stalk is seen in
about 20% of patients wim CNS involvement.
• Spinal disease manifestations are uncommon (about 5%
of patients with neurologic disease) and can have a
wide variety of presentations, including spinal cord
findings (e.g., myelopathy due to spinal cord compression
or infiltration) and involvement of single or multiple
nerve roots.
• The clinical diagnosis of neurosarcoidosis is based on
typical neurologic features, histopathologic evidence of
systemic disease (e.g., from skin, bronchial washings,
or lymph nodes), and CSF analysis (typically showing
decreased glucose content, elevated protein, and elevated
white blood cell count) .

Front 156

A 57-year-old woman with fever, confusion, and a nonfoca1 neurologic examination

Back 156

Nonhemorrhagic contusion: Tlus diagnosis might be
considered because the anterior portion of the temporal
lobe is a region that is affected frequently in closed
head injury. The absence of a history of trauma
excludes tllis diagnosis. Furtl1ermore, abnormal signal
is seen in regions that would be atypical sites for contllsion-
e.g., lie insula.
• Infarction: Infarction confu1ed to lie anterior portion
of tl1e temporal lobe is lillusual. Instead, infarction
usually involves eilier lie lateral two-tl1irds of lie
temporal lobe (nuddle cerebral artery territory) or tl1e
medial tlurd of the temporal lobe and tl1e occipital
lobe (posterior cerebral artery territory) .
• Tumor: Low-grade infiltrating gliomas and neoplasms
such as gliomatosis cerebri can produce abnormal MR
signal wili little or no contrast enhancement.
However, lie bilateral abnormality confined to lie
temporal lobes and insula in Figure 6- 1 7C would not
be expected wili tumor.
• Herpes simplex type 1 (HSV 1 ) encephalitis: This is
lie correct diagnosis given lie clinical history, primary
involvement of both temporal lobes and the insula,
and relative paucity of contrast enhancement.
DIAGNOSIS: Herpes simplex virus type 1
encephalitis.
+ KEY FACTS
CLINICAL
• The term encephalitis refers to a diffuse parenchymal
inflammatory process tl1at may be caused by a wide
variety of etiologies, but most commonly has a viral
etiology.
• The most common cause of nonepidemic acute viral
encephalitis in immunocompetent patients in tl1e
United States and Europe is HSV type 1 (oral strand)
infection. However, HSV 1 accounts for only about
1 0% of viral encephalitides.
• Nearly all adults have been exposed to liis virus,
which is responsible for "cold sores. "
• HSV 1 encephalitis i s thought to usually result from
reactivation of latent viral infection of the trigenlinal
ganglion. The infection extends in a retrograde fashion
323
along lie meningeal innervation of lie nuddle cranial
fossa and inferior portion of tl1e anterior cranial fossa.
• ClilUCal features include seizures, encephalopaliy,
headache, and low-grade fever.
• Because untreated HSV 1 encephalitis has a high mortality
rate, prompt treatment with acyclovir is essential .
Brain biopsy is lie most specific means of diagnosis
but is often deferred when lie diagnosis is highly likely
based on clinical, laboratory, and radiologic findings.
In such cases, acyclovir tl1erapy is started wi liout a
defilutive diagnosis.

Front 157

A 1 3-year-old girl with weakness in both legs and incontinence.

Back 157

KEY FACTS
CLINICAL
• There are three major types of inu'amedullary spinal
cord tumors: gliomas, ependymomas, and hemangioblastomas.
The first two are malignant and the
third is histologically benign.
• Gliomas account for about half of adult spinal cord
tumors, but they account for a higher percentage in
children. The peak incidence is in the third and fourth
decade. They are most common in the thoracic region,
are not usually encapsulated, and usually have ill-defined
borders. They are most common in the thoracic region.
These tumors tend to extend over the length of a few
vertebral boclies but can be much longer.
• Ependymomas arise from ependymal cells in the central
spinal canal. Thus, they tend to be central in location
and expand the cord outward . They are soft
tumors that usually have a delicate capsule that forms a
plane of cleavage that allows surgical excision without
damage to spinal cord tissue. They frequently form
cysts. Ependymomas arising in the filum terminale are
typically of the myxopapillary type, which are mucinous
and may bleed, causing subarachnoid hemorrhage.
They may be associated with extremely high
levels of protein in the CSF. Ependymoma is the most
common primary tumor of the lower spinal cord and
the filum terminale. Two-thirds of intramedullary
tumors at the conus medullaris are ependymomas.
Following total removal of the tumor, there is only a
small chance of recurrence (about 1 0% ) . If the absence
of a well-defined capsule prevents total excision, tumor
progression, often accompanied by metastases to the
CSF or even to clistant metastases, is common.
• Hemangioblastoma is a much less common primary
spinal cord tumor (about 3%) than glioma and ependymoma.
About 30% of patients Witll spinal cord hemangioblastoma
have von Hippel-Lindau syndrome
(VHL). However, <5% of VHL patients are reported
to have spinal hemangioblastomas, although the common
use of MRI to screen these patients may show
that the incidence is, in fact, much higher.
• Most spinal hemangioblastomas are intranledullary.
About half are associated with cysts. They are usually
associated with dilated veins on the surface of the cord.
Development of a long syrinx cavity is very common.
325
RADIOLOGIC
• The typical appearance of a spinal cord glioma on MRI
is an infiltrative mass that is hypointense on T 1 -
weighted images and hyperintense o n T2-weighted
images. The tumors essentially always contrast-enhance
in an inhomogeneous manner and have poorly defll1ed
borders. Associated cysts are frequently seen at the cranial
and caudal ends of the tumor. These cysts are typicaUy
benign and do not contrast-enhance. Malignant
cystic portions of the tumor, on the other hand, typically
rim-enhance.
• Ependymoma tends to arise in the center of the spinal
cord and clisplaces the normal tissue toward the
perimeter. The typical appearance is a mass in the center
of the spinal cord extencling both cephalad and
caudad over a number of segments. The lesions generally
homogeneously contrast-enhance and have welldefined
margins. Focal sites of hemorrhage can
occasionally be seen as hypointense areas on T2-
weighted images.
• If the conus is involved as well as the filum terminale,
tlle cliagnosis is very likely to be ependymoma. The
probability is further increased if the filum terminale is
involved in isolation, in which case the myxopapillary
type of ependymoma is highly likely.
• Hemangioblastomas appear as a focal, markedly
enhancing nidus, often with an adjacent cyst and
marked edema. A syrinx cavity is quite common. There
are frequently very small associated vascular foci elsewhere
in the spinal cord, particularly if the patient has
VHL. Multiple associated vessels are often seen, particularly
on the dorsal aspect of the spinal cord. They can
sometimes be seen on myelography as focal enlargement
of the spinal cord with serpiginous filling defects
due to tlle presence of vessels on the dorsal surface of
the spinal cord . These vessels can be mistaken for evidence
of a dural arteriovenous fistula or a spinal cord
arteriovenous malformation.

Front 158

A 37-year-old woman with multiple renal cysts and bilateral renal cell
carcinomas (RCCs).

Back 158

Metastasis: This diagnosis might be considered
because multiple lesions are present in a patient with
RCC. However, the appearance is atypical for metastasis.
The cystic lesions shown above consist of a cyst
and a peripheral mural nodule, whereas cystic regions
within metastasis (due to necrosis) are usually central .
Although RCC metastases can be vascular, the actual
presence of flow voids within the masses would be a
very unusual finding.
• Juvenile pilocytic astrocytoma: This diagnosis might
be considered because of the presence of a cyst with a
contrast-enhancing mural nodule in the case shown
above . Tlus tumor is usually seen in children and
young adults, but the age of the patient shown above
does not exclude the diagnosis. However, these tumors
are typically solitary and would not be expected to
have the internal flow voids shown above.
• Hemangioblastoma: This is the correct diagnosis
based on the presence of multiple posterior fossa cystic
lesions having densely enhancing mural nodules in a
young adult. I nternal flow voids due to hypervascularity,
as shown in the case above, are occasionally seen in
this tumor, further supporting the diagnosis.
+ DIAGNOSIS: Hemangioblastoma.
+ KEY FACTS
CLINICAL
• Hemangioblastoma is a benign tumor of the CNS
accounting for 1 .0% to 2 . 5% of all intracranial neoplasms.
The tumor is most commonly found in the
cerebellum and, less commonly, in the spinal cord.
Supratentorial hemangioblastomas are rare .
• The most common age at the time of discovery is the
third through fifth decades. There is not a strong
predilection for either gender.
• The tumor is histologically belugn. Neurologic features
occur on the basis of location-e.g., mass effect
of posterior fossa lesions and involvement of spinal
motor or sensory tracts by spinal lesions.
• Many patients with hemangioblastomas have an inherited
genetic disorder termed von Hippel Lindau
327
(VH L ) . Diagnostic criteria include at least one CNS
hemangioblastoma in association with one of the following
features: multiple cysts or neoplasms of the visceral
organs or a family history of VHL.
• Sites of visceral organ system involvement in VHL
include kidneys ( RCC, cysts) , pancreas (multiple cysts,
microcystic adenoma or adenocarcinoma), adrenal
gland (pheochromocytoma, wluch can also occur at
other sites) , epididynus (cysts) , and liver (adenomas,
cysts) .
• Polycythemia i s seen i n some cases due t o secretion of
erythropoietin by the tumor.
RADIOLOGIC
• One-third of hemangioblastomas have a purely solid
structure, one-third have a characteristic cyst with
peripheral mural nodule (Figure 6- 1 9A), and the
remainder are cystic but with a more complex solid
component than a simple mural nodule.
• Complete evaluation of patients with VHL should
include MRI of both the brain and spine.
• On noncontrast CT and MRI, the cyst contents can
often be seen to differ slightly from CSF due to a high
protein content.
• Solid components of hemangioblastomas densely contrast-
enhance on CT and MRI due to their high vascularity
associated with breakdown of the blood-brain
barrier.
• On MRI, flow voids can sometimes be seen within
solid portions of hemangioblastomas ( Figures 6 - 1 9 B
and 6- 19C) due to ( 1 ) either feeding or draining vessels,
or ( 2 ) large sinusoids within the tumor.
• At catheter angiography, the solid components are
seen to have enlarged feeding arteries and densely stain
with contrast material. Cystic portions of the tumor
are seen as avascular regions next to the nodule.

Front 159

A 4-month-old boy with facial nevus.

Back 159

Meningitis: Prominent involvement of only a portion
of one hemisphere with sparing of the remainder of
the brain would be an atypical leptomeningeal
enhancement pattern to be caused by meningitis. In
addition, this diagnosis would not explain the facial
nevus, the asymmetric size of the hemispheres, or the
enlargement of the choroid plexus.
• Leptomeningeal carcinomatosis: This diagnosis would
be unlikely because of many of the reasons cited against
the diagnosis of meningitis. In addition, however, leptomeningeal
infiltration by tumor would be distinctly
unusual in a child of the age in the case shown above.
• Subacute infarction: Leptomeningeal enhancement
can be seen in the first few days after cerebral infarction.
Stroke in a child of the age in the case shown
above is, however, quite uncommon. Furthermore,
this diagnosis would not explain the other findings,
which suggest a congenital cause.
• Sturge-Weber syndrome: The findings of leptomeningeal
enhancement, underlying cortical atrophy
and enlargement of the choroid plexus, as seen in the
case shown above, are typical for this disorder.
DIAGNOSIS: Sturge-Weber syndrome.
KEY FACTS
CLINICAL
• The Sturge-Weber syndrome, also known as
encephalotrigeminal angiomatosis, is a congenital neurocutaneous
syndrome in which the main features are a
facial cutaneous vascular nevus (port-wine stain), a leptomeningeal
venous angiomatosis associated with cerebral
cortical calcifications, and angiomatosis of the
choroid of the eye.
• Congenital glaucoma, seizures, hemiparesis, hemianopsia,
and mental retardation (two-thirds of cases) are
the major clinical manifestations.
• The facial nevus is in tlle distribution of the trigeminal
nerve, usually the first division, and typically ipsilateral to
the intracranial lesions. However, only 1 0% of patients
with such facial nevi have Sturge-Weber syndrome. In
the remaining 90%, the facial nevus is a solitary dermatologic
abnormality without associated findings.
• The intracranial lesion is a leptomeningeal vascular malformation,
which is usually unilateral in the parietaloccipital
region and ipsilateral to the facial nevus. A
plethora of small, thin-walled structures, which resemble
telangiectatic capillaries or venules, are seen to lie
along the surface of the brain between the pia and the
arachnoid membranes. The underlying cerebral cortex
becomes dysfimctional and atrophic, and often calcifies.
Abnormal venous drainage of the cortex develops, with
increased collateral flow through the choroid plexus.
• Seizures are often the initial neurologic feature, frequently
beginning in tlle first year of life and thereafter
329
relentlessly progressing with advancing age. Progressive
hemianopsia and hemiparesis contralateral to the leptomeningeal
vascular abnormality are often seen.
• The choroid of the eye is involved by an angioma in
30% of cases, often causing buphthalmos ( e nlargement
of the eye, or "cow eye"), a form of congenital glaucoma.
• Angiomas can be seen in otller organs, including the
kidneys, spleen, ovaries, intestines, adrenals, thyroid,
pancreas, heart, thymus, and lungs.
• Laser therapy of the facial nevus yields cosmetic
improvement. Intractable seizures in Sturge-Weber
patients can be surgically treated by lobectomy or
hemispherectomy and corpus callosum resection, if the
patient is of a sufficiently young age (i.e., <2 years of
age) that the remaining hemisphere can assume motor
and sensory function for both sides of the body.RADIOLOGIC
• A gyriform pattern of calcification is often seen at the
site of the leptomeningeal vascular malformation. This
finding is due to foci of calcification within the cerebral
cortex rather than vascular calcifications. It is best
seen on CT but can also be seen on plain radiographs
and MRI, on which it is best delineated on gradient
echo images.
• Other CT findings include cortical atrophy and
enlargement of the choroid plexus. The extent of
involvement as judged by cortical atrophy is often
more extensive than the sites of parenchymal calcification.
Cortical enhancement can be seen on contrastenhanced
CT, thought to be reflect impaired
superficial cortical venous outflow associated with the
leptomeningeal venous angioma.
• Findings on T2 -weighted MRIs include hyperintense
signal abnormality in areas of gliosis, ischemia, and
demyelinization and hypointense gyriform signal due
to cortical calcifications. As a reaction to tlle brain
atrophy, the adjacent calvarium can thicken and the
paranasal sinuses hypertrophy, changes that have been
termed the Dyke-DavidofJ-Masson syndrome.
• On contrast-enhanced T 1 -weighted MRIs, marked
enhancement of the leptomeninges overlying the
involved hemisphere, the enlarged choroid plexus
( "choroidal angiomatosis" ) , enlarged deep medullary
veins, and a retinal angioma can often be seen.
• At catheter angiography, abnormalities of the superficial
cerebral venous drainage just deep to the area of
leptomeningeal angiomatosis can be seen.

Front 160

A 38-year-old woman with unremitting left-sided headache and oculosympathetic
paresis of 2 weeks' duration.

Back 160

Atherosclerotic narrowing: This diagnosis would be
unlikely in a young patient and would not be expected
to cause the symptoms mentioned above . Furthermore,
the site of arterial narrowing is above the level
of the carotid bifurcation and extends into the level of
the skuU base. Atherosclerotic narrowing, on the other
hand, typicaUy occurs at the carotid bifurcation and
does not extend the length of the internal carotid
artery ( ICA) .
• Vasospasm: Arterial spasm in the extra cranial portion
of the ICA could be seen after trauma due to catheter
placement or external trauma but does not usually
affect a long segment of the artery and would not
explain the MRI findings.
• Arterial dissection: This entity typically shows abnormal
periarterial signal on MRI and increase in the
external diameter of the artery ( as in Figure 6-2 IA)
due to intramural hemorrhage. Luminal narrowing
over a variable length of the artery is commonly seen
beginning a few centimeters above the carotid bifurcation
(as in Figure 6-2 I B ) . Tllis is the correct diagnosis.
• DIAGNOSIS: Arterial dissection.
KEY FACTS
CLINICAL
• Dissections cause approxinlately 1 % to 2% of all strokes
in the general population but between 5% and 20% of
strokes among patients <40 years old.
• Dissection can occur after trauma, on a spontaneous
basis, or after movements of the head or neck that are
generally considered benign ("trivial trauma" ) .
• Headache or neckache i s present i n about 7 5 % of
patients. Oculosympathetic paresis ( Horner's syndrome)
is commonly seen in ICA dissection.
• Transient ischemic attacks and completed strokes occur
in a minority of patients.
• Subarachnoid hemorrhage can accompany intracratlial
dissections.
• The most common sites are the cervical portion of the
ICA (within a few centimeters of the carotid bifurca-
331
tion) and the vertebral artery at the level of the C I -2
vertebral bodies.
• Anticoagulation for a period of a few months is usually
performed when subarachnoid hemorrhage is not
present.
RADIOLOGIC
• The most common finding at catheter angiography is a
site of smooth or irregular narrowing extending over a
few centimeters in length. Other catheter angiography
f1l1dings can include pseudoaneurysm formation, arterial
occlusion, and, less commonly, atl intimal flap. A
double-lumen appearance is rare .
• The typical MRI finding is a narrowed arterial lumen
( flow void) with an adjacent crescentic area of abnormal
signal ( usually hyperintense on T l - and T2 -
weighted images) .
• At M R angiography, a narrowed arterial signal column,
frequently with an adjacent region of hyperintense signal
aligned parallel to the artery, can often be seen.
• Diagnostic features at ultrasonography include an
echogenic intimal flap ( the most specific sign, but
present in only a minority of cases) and echogenic
thrombus.
• CT is not usually performed to establish the diagnosis,
but contrast-enhatlCed CT can demonstrate a narrowed
arterial lumen with an eccentric region of mural
thickening.
• Resolution or significant improvement at me time of a
repeat imaging study performed a few weeks later is
seen in about 80% of treated cases.

Front 161

A 5 1 -year-old woman with visual field defect and headache.

Back 161

Meningioma: This might be considered because the
lesion is extra-axial and densely contrast-enhances.
However, this diagnosis would not account for the
abnormal signal in both temporal lobes.
• Craniopharyngioma: This diagnosis might be considered
because a portion of the mass extends into the
suprasellar cistern. However, craniopharyngiomas are
typically cystic, often calcified, and do not generally
diffusely contrast-enhance.
• Epidermoid cyst: This diagnosis might be considered
because of the extra-axial suprasellar location of the
lesion. However, epidermoids usually appear moderately
hyperintense on T2 -weighted images and do not
contrast-enhance.
• Pituitary adenoma: On Figure 6-22B, the posterior
lobe of the pituitary gland is seen between the two
internal carotid arteries ( ICAs) . The lesion is clearly
separate from the pituitary gland.
• Aneurysm: This diagnosis should be considered when
a mass lesion is seen in the region of the circle of
Willis. A wide range of signal intensities can be seen
due to slow blood flow within an aneurysm or partial
or complete thrombosis. Therefore, the fact that a normal
flow void is not present in the lesion by no means
excludes this diagnosis. The abnormal signal seen in
the temporal lobes is a clue to the correct diagnosis.
This signal is due to pulsation artifact in the phaseencoding
direction produced by flow within the mass,
which is an aneurysm.
+ DIAGNOSIS: Giant aneurysm.
KEY FACTS
CLINICAL
• Giant aneurysms are >25 mm in diameter and account
for approximately 5% of all intracranial aneurysms.
• Presentation usually is in the fourth through sixth
decades. Giant aneurysms typically become symptomatic
due to mass effect on adjacent intracranial structures
(which may raise clinical suspicion of a neoplasm )
rather than aneurysmal rupture.
• Giant intracranial aneurysms are associated with substantial
neurologic morbidity or death within 5 years
of diagnosis if untreated.
• The optimal treatment options include ( 1 ) clipping of
the neck of the aneurysm with preservation of the parent
vessel, or ( 2 ) endovascular occlusion of the
aneurysm by balloons or embolic coils. Less optimally,
carotid artery ligation or wrapping of the aneurysm is
performed in the uncommon instance in which the
aneurysm cannot be treated definitively.
333
RADIOLOGIC
• About half of giant aneurysms involve the ICA and its
distal branches. The most common sites in the carotid
circulation are near the origin of the ophthalmic artery,
ICA bifurcation, and cavernous segment of the lCA.
The most frequent sites in the vertebrobasilar system are
at the tip of the basilar artery, junction of the basilar and
superior cerebellar arteries, and vertebrobasilar jW1Ction.
• At catheter angiography, partially thrombosed giant
aneurysms often appear smaller than their actual size,
which can be more accurately defined by CT and M R! .
• The CT and MRI appearance o f a giant aneurysm can
be mistaken for a tumor. In particular, giant aneurysms
in the parasellar region and at other sites near the skull
base can be mistaken for a meningioma. It is important
to consider this entity in the differential diagnosis
of masses in these regions if inadvertent biopsy or
improper surgery is to be avoided.
• On noncontrast CT, aneurysms appear as rounded or
oval masses that are relatively isodense or, frequently,
hyperdense relative to adjacent brain tissue. Partially
thrombosed aneurysms often have a hyperintense crescentic
rim. Occasionally, the rim of an aneurysm can
be seen to be calcified. Following contrast administration,
non thrombosed aneurysms densely and homogeneously
contrast-enhance, while generally only the
patent lumen of partially thrombosed aneurysms
densely contrast-enhances.
• On MRI' a non thrombosed aneurysm is seen as an
oval or spherical extra-axial region of absent signal
( flow void), continuous with a vessel . Partially
thrombed aneurysms typically have a laminated appearance,
due to layers of hemorrhage of different age.
Occasionally, a thin circumferential region of abnormal
perianeurysmal signal due to chronic hemorrhagic
products can be seen.
• An important clue that a mass lesion seen on MR! is an
aneurysm is a band of pulsation artifact extending from
tlle aneurysm into adjacent tissues along the phaseencoding
axis. This artifact is often increased after
administration of contrast material ( Figure 6-22C ) .

Front 162

A 76-year-old woman with progressive visual deficits and headache.

Back 162

Rathke's cleft cyst: This lesion typically has hyperintense
signal on noncontrast T 1 -weighted images due
to proteinaceous composition. Contrast enhancement
is not seen. Therefore, this is the incorrect diagnosis
for the case shown above.
• Craniopharyngioma: This lesion nearly always is centered
in the suprasellar cistern, although an intrasellar
component is often present. The vast majority are calcified
and cystic, features not seen in the case shown
above. Because craniopharyngioma can have a uniformly
contrast-enhancing appearance suggesting a solid mass,
the diagnosis cannot be absolutely excluded based on the
imaging findings shown above but is considered unlikely.
• Aneurysm: This diagnosis might be considered because
the lesion shown above is oval and close to the I CA.
The absence of a flow void within the lesion is not evidence
against the diagnosis of aneurysm, because
aneurysms are frequently partially thrombosed. However,
pulsation artifact in the phase-encoding direction,
indicative of flow, would be expected in a nonthrombosed
or partially thrombosed aneurysm. Such artifact is
not present. In addition, sellar enlargement and the
symmetric constriction seen in the middle of tlle lesion
shown above would be atypical for an aneurysm.
• Meningioma: Meningioma is a consideration because
of the homogeneous enhancement pattern. However,
meningiomas are typically juxtasellar and rarely intrasellar.
Furthermore, in the case of meningioma, the mass
should be separable from the pituitary gland. The mass
illustrated here is inseparable from the pituitary gland.
• Pituitary microadenoma: By definition, microadenomas
are < l cm in size. They do not extend to the suprasellar
cistern and should appear as hypointense regions within
an otherwise normally enhancing pituitary gland.
• Pituitary macroadenoma: This term refers to adenomas
> 1 0 mm in size. This is the correct diagnosis
given the large size, intrasellar location, and diffuse
enhancement pattern. This mass has grown superiorly,
expanding the infundibular orifice of tlle diaphragma
sella, producing a bilobed appearance.
+DIAGNOSIS: Pituitary macroadenoma.
KEY FACTS
CLINICAL
• Adenomas are the most common neoplasm of the
pituitary gland and arise in the adenohypophysis (anterior
lobe of tlle pituitary gland ) . They comprise 1 0% to
1 5% of all intracranial tumors.
• Many hormonally active pituitary adenomas become
clinically apparent while small. Three-fourths of all
adenomas present with signs and symptoms related to
hormonal overproduction.
• Many nonfunctioning tumors grow to large size before
producing symptoms. One-fourth of all adenomas present
with symptoms due to mass effect-e.g., headache,
335
visual field defects, cranial nerve palsies, and cerebrospinal
fluid ( CSF) rhinorrhea due to sellar erosion.
• Hormonally active adenomas may secrete prolactin:
thyroid-stimulating hormone, growth hormone,
adrenocorticotropic hormone, follicle-stimulating hormone,
and luteinizing hormone, alone or in various
combinations. Hormonally inactive adenomas have
been termed "null cell" adenomas or oncocytomas.
RADIOLOGIC
• Unless contraindicated, MRI is generally considered
the first-line imaging study for detection of pituitary
adenomas.
• During the evaluation of the lesion of the sellar/juxtasellar
region, the radiologist's role is to establish the center
of the lesion and its relationship to adjacent structures.
Relevant features include the relation to the optic structures,
course and caliber of the cavernous segment of the
ICAs, and whether the cavernous sinuses are invaded.
• Pituitary adenomas can be diagnosed on any MRI
pulse sequence, but contrast-enhanced T l -weighted
images in the coronal plane are probably the technique
that is most widely accepted. Nonetheless, they can be
detected on noncontrast T l -weighted images as a
hypointense region and in 30% to 50% of cases as a
hyperintense lesion on T2-weighted images. The latter
finding is more common in macroadenomas.
• MRI is optimally performed within a few minutes of
contrast infusion. Microadenomas contrast-enhance less
rapidly than the normal pituitary tissue in that time
period and appear relatively hypointense to the normal
gland. Further delay in imaging can lead to false-negative
studies, because over many minutes, the lesion contrastenhances
to the same degree as normal pituitary tissue.
• Macroadenomas are typically isointense to gray matter
on all pulse sequences and intensely contrast-enhance,
often in an inhomogeneous manner.

Front 163

A 1 2-year-old girl with seizures and headache.

Back 163

ventricle includes:
• Choroid plexus papilloma: This lesion might be considered,
because it is an intraventricular mass that is
seen more frequently in children than adults. However,
because it arises from choroid plexus, it is typically
found in the atrium of the lateral ventricle and not near
the foramen of Monro, as in the case shown above .
• Neurocytoma: This lesion typically arises in the lateral
ventricle and is attached to the septum peUucidum. On
the images shown above, it is difficult to determine
whether the mass is attached to the septum peUucidum
or merely abuts it. However, this diagnosis would not
accOlmt for the presence of the multiple regions of
hyperintense signal within brain parenchyma and the
hypo intense lesion in the right ventricle on the T2-
weighted images.
CASE #24 N euroradiology
• Meningioma: Meningiomas can arise within the ventricular
system, but when they are located in the lateral
ventricle, they are almost always attached to the
choroid plexus, unlike the lesion shown above .
Furthermore, as in the case of choroid plexus papilloma
and neurocytoma, the diagnosis of meningioma
would not adequately account for the parenchymal signal
changes and the hypointense nodule seen on the
ependymal surface of the right lateral ventricle.
• Subependymal giant cell tumor (SGCT): These
tumors arise at the foramen of Monro, as in the case
shown above. In the vast majority of cases, these
tumors are seen in association with clinical and radiologic
findings of tuberous sclerosis (TS ) . This diagnosis
would account for the cortical and subcortical hyperintense
signal ( representing hamartomas) and the lesion
on the surface of the right lateral ventricle (a calcified
subependymal nodule ) .
+ DIAGNOSIS: Subependymal giant cell tumor in
a patient with tuberous sclerosis.
+ KEY FACTS
CLINICAL
• TS is a phakomatosis with an autosomal dominant
inheritance pattern associated with deletion on
chromosome 9 and, in some cases, chromosome
1 1 . However, about half of cases are spontaneous
mutations.
• Initially, the disease was diagnosed by a clinical triad of
adenoma sebaceum, seizures, and mental retardation,
as described by Vogt. Although these three features are
commonly seen, this has been replaced by a more
inclusive set of diagnostic criteria (see below) .
• The disease i s characterized by the presence o f hamartomas
in multiple organs. In addition to brain, the skin
(adenoma sebaceum in 95% of patients), eye (retinal
hamartomas, 50%), kidneys ( angiomyolipomas in 50%
to 80%, renal cysts, and renal artery aneurysms), heart
( rhabdomyomas, 30%), skeleton (multiple sclerotic
bone islands), and, less commonly, the lungs (smooth
muscle proliferation within the interstitial tissues, more
common in women) are affected.
• Adenoma sebaceum is a form of facial angiofibroma.
Subungual fibromas are another cutaneous manifestation
of the disease.
• The retinal hamartomas are small rounded masses that
overlie the optic nerve head, are histologically similar
to subependymal tubers, and commonly calcifY.
• Hamartomas are seen in two major locations in the
brain : within the parenchyma (cortical and subcortical
regions) and at subependymal sites. Histologically, these
lesions consist of disorganized conglomerations of
337
poorly differentiated neurons and are thought to result
from disordered migration and differentiation of glial
tissue.
• Subependymal hamartomas are typically arranged along
the caudothalamic groove. In 1 5% of TS patients, they
undergo malignant degeneration into a SGC

Front 164

An I I -year-old boy with mental retardation.

Back 164

Interhemispheric cyst: A congenital or acquired cyst
located in the interhemispheric region could produce a
space filled with cerebrospinal fluid ( CSF) between the
hemispheres but would not alone account for the
abnormal shape of the ventricles and cingulate gyrus
or the abnormal white matter tracts along the medial
aspects of the ventricular surfaces.
• Agenesis of the corpus callosum (ACC): This is the
correct diagnosis based on the abnormal CSF-filled
space cephalad from the third ventricle ( "high-riding
third ventricle" ) , abnormal configuration of the ventricles
and cingulate gyrus, and abnormal white matter
tracts along the medial aspects of the ventricular surfaces
(which are due to conglomeration of white matter
fibers that run parallel to the medial walls of the
lateral ventricles-the so-called bundles of Probst) .
+ DIAGNOSIS: Agenesis of the corpus callosum.
+ KEY FACTS
CLINICAL
• The corpus callosum is formed between the eighth and
twentieth weeks of gestation. The parts of the corpus
callosum form in a specific order: genu, body, splenium,
and rostrum.
• Three forms of callosal dysgenesis are recognized:
ACC, hypogenesis (i.e., incomplete formation), and
hypoplasia (resulting from an insult to cortex or white
matter after the corpus callosum has been formed ) .
• A wide spectrum o f potential mechanisms ( e.g., infectious,
toxic, metabolic, and mechanical) by which ACC
can occur have been reported, but in the vast majority
of instances, the exact etiology is not known.
• ACC usually occurs as an isolated finding but can be
seen with other structural abnormalities of the braine.
g., Dandy-Walker malformation, neuronal migration
abnormalities, septo-optic dysplasia ( hypoplasia of the
optic discs, absence of the septun1 pellucidum, and
hypopituitarism ), Aicardi's syndrome (seizures, ocular
abnormalities, and mental retardation) , and malformations
of the face (e.g., cleft lip or palate, hypertelorism,
and hypoplastic mandible ) .
• ACC i s often, but b y n o means always, associated
with mental retardation (which is usually due to
339
associated abnormalitie s ) . The incidence of callosal
dysgenesis is 5 to 10 times higher in individuals with
developmental delay than in individuals with normal
cognitive development.
RADIOLOGIC
• CT findings include ( 1 ) absence of all or part of the
corpus callosum, ( 2 ) a CSF-filled space extending
cephalad from the third ventricle, ( 3 ) a parallel appearance
of d1e lateral ventricles, and (4) dilatation of the
occipital horns and posterior portions of d1e temporal
horns ( "colpocephaly") (Figure 6-25A) .
• The term high-riding third ventricle is often used to
refer to the abnormal cephalad extension of this ventricle
. The cephalad portion of the ventricle is often
dilated and can simulate an interhemispheric cyst.
• Colpocephaly associated with ACC is d10ught to be
due to the combination of absence of d1e splenium of
the corpus callosum and underdevelopment of the forceps
major.
• MRI is more sensitive than CT in displaying the structural
abnormalities in ACe. On sagittal MR images, the
medial hemispheric sulci can be seen to extend down to
the third ventricle (Figure 6-2 5C). These gyri normally
terminate at the cingulate sulcus. In the normal brain,
inversion of the cingulate gyri occurs in association with
the crossing of white matter fibers in the corpus callosum.
For this reason, in patients with ACC, the cingulate
gyri remain everted (and formation of the normal
cingulate sulcus and gyrus does not occur) .
• On coronal MRIs, the lateral ventricles can be seen to
have a crescentic shape (with a medial wall that is
straight or concave) due to impression on their medial
surface by heterotopic bundles of axonal fibers that
have failed to cross the midline (longitudinal bundles
of Probst) . These bundles lie between the cingulate
gyri and the ventricular surface (Figure 6-25B ) .

Front 165

An I S-month-old girl with vomiting.

Back 165

Medulloblastoma: This tumor might be considered
because it is a common posterior fossa neoplasm of
childhood. This tumor usually arises from the cerebellar
vermis and bulges forward from the roof of the
fourth ventricle. The fourth ventricle would be
expected to be displaced anteriorly (see Case 2 7 ) .
However, i n this case, the fourth ventricle i s displaced
posteriorly. Furthermore, extension into the cere bellopontine
angle by medulloblastoma is W1Common.
• Choroid plexus papilloma: In childhood, choroid
plexus papillomas usually occur in the lateral ventricle,
wilike the case shown above . Occurrence in the fourth
ventricle is usually seen in adults. Furthermore, unlike
the lesion shown above, choroid plexus papilloma generally
contrast-enhances diffusely and has internal signal
voids due to a high degree of vascularity.
• Ependymoma: Fourth ventricular ependymomas typically
arise in the floor of the fourth ventricle, thereby
displacing the ventricle posteriorly ( as in the case
shown above ) . They often extend through the foramen
of Luschka and up to ( and sometimes around) the
anterior surface of the lower brain stem.
+ DIAGNOSIS: Ependymoma.
+ KEY FACTS
CLINICAL
• Intracranial ependymoma is largely a tumor of children
and adolescents but does occur in adults. Most cases
present prior to 5 years of age.
• Approximately 60% of brain ependymomas are
infratentorial. The remaining 40% are supratentorial
and typically occur in either a parenchymal or periventricular
location.
• Infratentorial ependymoma arises from the ependymal
lining of the fourth ventricle and is predominantly
intraventricular. It is not uncommon for the tumor to
invade the brain stem. Growth along adjacent brain
cisterns is characteristic. The term plastic ependymoma
is given to an ependymoma that has grown around the
anterior surface of t11e brain stem or spinal cord.
• Fourth ventricular ependymoma often presents with
signs and symptoms of obstructive hydrocephalus
(headache, vomiting) . Less often, gait or limb ataxia,
341
nystagmus, or cranial nerve dysfunction is a presenting
feature.
• CSF dissemination is uncommon ( about 1 0% of cases)
at the time of presentation but is more common at a
time of relapse.
• Treatment is generally surgical resection and radiation
therapy. Prognosis is relatively poor, especially in
young children with subtotal resection ( adult 5 -year
survival: approximately 70%; pediatric 5 -year survival:
approximately 1 5% ) .
• Ependymoma can arise i n the spinal cord a s an
intramedullary mass (see Case 1 8 ) . The myxopapillary
type characteristically arises from conus medullaris or
filum terminale.
RADIOLOGIC
• The correct preoperative diagnosis of infratentorial
ependymoma can be made based on location and morphology
of the mass. This is a solid fourth ventricular
mass, often with "plastic" extension into the cere bellopontine
angle via the foramen of Luschka or into the
foramen magnum via the foramen of Magendie.
• On noncontrast CT, posterior fossa ependymomas
appear relatively isodense to gray matter but are inhomogeneous,
with 50% having calcification and about
20% having cystic components. Inhomogeneous contrast
enhancement is typical.
• On MRI, ependymoma often has inhomogeneous signal
intensity due to hemorrhage, necrosis, cyst formation,
calcification, and hemosiderin deposition. Like most
tumors, the solid component is iso- or hypointense relative
to brain parenchyma on T l -weighted images and
hyperintense on T2-weighted images. Contrast enhancement
is usually inhomogeneous.
• Cyst formation is much more common in supratentorial
ependymomas (40% to 8 5% of cases) than infratentorial
lesions.

Front 166

A 6-year-old boy with headache and ataxia.

Back 166

Ependymoma: This tumor might be considered
because it is one of the common posterior fossa
tumors in the pediatric population and is usually
located within the fourth ventricle. However, ependymomas
are frequently inhomogeneous, and about 50%
are calcified. Furthermore, they typically arise in the
floor of the fourth ventricle. In the case shown above,
the fourth ventricle is displaced ventrally, indicating
that the mass originated in the roof of the fourth ventricle.
• Astrocytoma Uuvenile pilocytic astrocytoma): This
tumor is also one of the common posterior fossa
tumors of the pediatric population. Unlike the case
shown above, however, these lesions are typically cystic
and located in the cerebellar hemisphere.
• Medulloblastoma: This tumor typically arises from
the roof of the fourth ventricle and is homogeneous
and often hyperdense on noncontrast CT, all features
of the lesion shown above.
+ DIAGNOSIS: Medulloblastoma.
+ KEY FACTS
CLINICAL
• Medulloblastoma is a highly malignant tumor that is
usually seen between the ages of 3 and 1 0 years.
• Medulloblastoma is considered one type of primitive
neuroectodermal tumor, along with ependymoblastoma,
pinealoblastoma, and cerebral neuroblastoma.
• In childhood, the tumor typically arises in the midline,
originating in the cerebellar vermis and extending into
the fourth ventricle. When seen in young adults, it often
occurs off the midline, in the cerebellar hemispheres. A
2 to 1 male predominance has been reported.
• Metastasis through the subarachnoid space of the brain
and spine is common, being seen in 25% to 50% of
patients at the time of diagnosis or early in the postoperative
period.
• Because ventriculoperitoneal shunts are often placed in
these patients for hydrocephalus, peritoneal metastasis
can sometimes be seen.
• Medulloblastoma is one of the few CNS tumors that
metastasizes with any notable frequency outside the
central nervous system. Bone metastases are seen in
about 5% of cases.
• The 5-year survival rate is estimated at 40% to 80%.
RADIOLOGIC
• On noncontrast CT, the tumor appears as a weUmarginated,
homogeneous, hyperdense mass (Figure
6-27C) that arises from the vermis and fills the fourth
343
ventricle. The hyperdense appearance, although not
invariably present, is a helpful feature in identifYing the
mass as medulloblastoma. Small cysts are sometimes
seen. Calcification is seen in about 1 0% of cases, but it
is not a prominent feature when present.
• Medulloblastoma must be distinguished from two
other common pediatric posterior fossa tumors: cerebellar
juvenile pilocytic astrocytoma (JPA) and ependymoma.
JPA is usually hypodense on CT due to a large
cystic component, and ependymoma is usually isodense
or slightly hyperdense and calcified more commonly
( 50%) than medulloblastoma (and thus has an intrinsically
inhomogeneous appearance) .
• Following contrast administration, medulloblastoma
typically densely enhances in a homogeneous pattern
except for the usually small areas of necrosis. In comparison,
only tlle solid portions of JPAs contrastenhance,
resulting in an inhomogeneous appearance.
Ependymoma also often enhances in an inhomogeneous
pattern, further allowing distinction from
medulloblastoma in most cases.
• Atypical appearances of medulloblastoma at the time of
presentation can occasionally be seen, including a mass
that is wholly cystic, a mass arising in the cerebellopontine
angle, and multifocal tumor.
• On MRl, the tumor is hypointense on T1 -weighted
images and iso- or hyperintense on T2-weighted
images. The pattern of MR contrast enhancement is
similar to that seen on CT.
• Sagittal MRls are often helpful in distinguishing medulloblastoma
from ependymoma. Because medulloblastoma
typically originates in the roof of the fourth
ventricle, a cleavage plane can often be seen between the
mass and the brain stem (Figures 6-27A and 6-27B).
Ependymomas are often adherent to the floor of the
fourth ventricle and can grow into the brain stem. A
cleavage plane, therefore, is often seen between the posterior
aspect of the tumor and the vermis

Front 167

A 67-year-old woman with headache

Back 167

Acoustic schwannoma: This is the most common
cerebellopontine angle (CPA) cistern mass lesion.
However, this diagnosis is unlikely in the patient
shown above because the mass does not extend into
the internal auditory canal.
• Arachnoid or epidermoid cyst: Both of these lesions
are extra-axial and can occur in the CPA cistern.
Arachnoid cysts are isointense with cerebrospinal fluid
(CSF), unlike the lesion shown above. Epidermoid
cysts do not contrast-enhance or only minimally contrast-
enhance, unlike the lesion shown above.
• Meningioma: This is the best diagnosis because of the
extra-axial location of the mass, hypointense appearance
on T2-weighted images, dense contrast enhancement,
and the presence of a small portion of the lesion
extending along the dura (so-called dural tail).
+ DIAGNOSIS: Meningioma.
+ KEY FACTS
CLINICAL
• Meningioma is the most common nonglial intracranial
neoplasm.
• The peak incidence is the fifth through seventh
decades. The female-to-male ratio is 2 to l .
• Meningiomas are rare in the pediatric population.
Approximately 25% of children with a meningioma will
have neurofibromatosis.
• Meningiomas arise from meningothelial cells (arachnoid
"cap" cells) of the arachnoid villi and occur most
often where these cells are most numerous.
• Sites of occurrence, in order of decreasing frequency,
are parasagittal convexity, sphenoid wing, planum
spenoidale, supra- or parasellar region, falx, posterior
fossa, and spine. Less common sites include the cavernous
sinus, ventricle (especially trigone of the lateral
ventricle), and orbit. These lesions may rarely occur in
the diploic space and extracranial sites (nasal cavity,
paranasal sinuses, nasopharynx, infratemporal fossa).
• Four classic histologic subtypes are described:
meningothelial (syncytial), fibroblastic, transitional,
and angioblastic. Malignant meningiomas are rare.
RADIOLOGIC
345
• Most meningiomas are well-defined, extra-axial masses.
They may be broad-based, pedunculated, or flat ( "en
plaque").
• On CT, these lesions can be ( 1 ) isodense with brain,
(2) intrinsically homogeneously hyperdense, or ( 3 ) calcified
to varying degrees. They typically strongly contrastenhance.
Calcification is seen in 1 5% to 20% of cases.
Atypical findings (necrosis, cyst formation, hemorrhage)
occur in 1 5% of cases.
• On MRI, meningiomas are typically isointense (60%)
or hypointense ( 30%) relative to gray matter on noncontrast
T l -weighted images and usually densely
contrast-enhance. They are isointense (50%) or hyperintense
(40%) relative to gray matter on T2-weighted
images. However, densely calcified or fibrous tumors
can be very hypo intense on T2-weighted images
(Figure 6-28C). Peri tumoral hyperintense signal on
T2-weighted images due to edema is seen in 75% of
tumors.
• A "dural tail" is seen in approximately 60% of tumors
on MRI. This finding can represent either tumor or
non-neoplastic dural reaction. Although this fmding is
highly suggestive of meningioma, it is not specific for
meningioma because it can be seen in other entities

Front 168

A 73-year-old woman with right seventh nerve dysfunction

Back 168

Arachnoid cyst: This lesion might be considered
because the lesions shown above are nearly isointense
with CSF. However, arachnoid cysts are truly isodense
to cerebrospinal fluid (CSF) on CT and isointense on
all MR pulse sequences, unlike the lesions shown
above.
• Cysticercosis: Extra-axial lesions can be seen due to
cysticercosis infection in the "racemose" form of the
disease, in which cystic lesions are found within the
subarachnoid spaces and brain cisterns. The lesions can
grow to large size and compress adjacent brain. However,
they are typically isointense with CSF, unlike the
lesion shown above.
• Epidermoid cyst: These lesions are frequently located
in the cerebellopontine angle (CPA) and deform adjacent
brain. They are isodense or slightly hyperdense to
CSF on CT (Figure 6-29A). They are isointense to CSF
on one or more MR pulse sequences but, in the majority
of cases, differ in signal intensity from CSF on at
least one MR pulse sequence (Figures 6-29B and 6-
29C).
DIAGNOSIS: Epidermoid cyst.
+ KEY FACTS
CLINICAL
• Epidermoid cysts are thought to arise from inclusion
of epithelial elements within the neural groove during
its closure.
• Although epidermoid cysts grow with age, tlley are
not considered neoplasms. Enlargement occurs due to
progressive accumulation of breakdown products of
desquamated epithelial cells, including keratin and
solid cholesterol.
• Eighty percent of intracranial epidermoid cysts are
intradural in location, often appearing in the infratentorial
compartment. The CPA is one of the more common
sites. Supratentorial epidermoid cysts are usually
found in the parasellar region and medial aspect of the
middle cranial fossa.
• Epidermoid cysts are slow-growing lesions that conform
to the surface of the brain as they enlarge, infiltrate
through tlle subarachnoid space, and surround
vessels and cranial nerves. Symptoms have often been
present for many months or a few years by the time of
discovery.
• Because the surfaces of intracranial epidermoid cysts
have a shiny, white surface appearance, they are sometimes
referred to as "pearly nll11ors."
• Epidermoid cysts are similar to dermoid cysts in that
both lesions have a stratified squamous epithelial lining
347
with a fibrous connective tissue capsule, but epidermoid
cysts lack sebaceous and sweat gland secretory wuts.
• Arachnoid cyst is the principal diagnostic consideration
from wluch epidermoid cyst must be distinguished.
This is true because arachnoid cysts are frequently not
treated because tlley are asymptomatic, stable congenital
lesions. Epidermoid cysts, however, are often symptomatic
and continue to grow with advancing age,
necessitating resection.
• Total surgical resection of an epidermoid cyst is often
impossible because portions of tlle lesion are buried in
spaces tllat caJmot be reached without causing undue
traction on important neurologic or vascular strucnlres
and because the tumor is often tightly adherent to
brain aJld blood vessels. In those instances, partial
debulking is performed, which may need to be
repeated as the lesion regrows.
RADIOLOGIC
• On noncontrast head CT, epidermoid cysts are hypodense
extra-axial masses whose margins are often
slightly lobulated or scalloped. Many lesions are slightly
hyperdense relative to CSF and n1ildly inl1omogeneous.
However, they frequently are isodense to CSF, making
distinction from araclmoid cyst difficult. Occasionally, a
very small an10unt of calcification can be seen.
• Epidermoid cysts have a soft, pliable consistency, but
tlley often exert a moderate degree of mass effect on
adjacent brain structures.
• Lack of enhancement after contrast adn1inistration is
the general rule, although sometimes very nlild contrast
enllancement can be seen around the rim of the lesion.
• MRl is frequently useful in distinguishing epidermoid
cysts from arachnoid cysts because the lesion often
appears inhomogeneous aJld has a signal intensity that
differs from CSF on at least one pulse. MRl is also
important in surgical plaruung because it is the best
method for defining tlle limits of the mass and tlle spatial
relationship to cranial nerves and blood vessels.
• When a suspected epidermoid cyst is isointense with
CSF on all pulse sequences, tlle distinction from arachnoid
cyst can be made by pulse sequences tllat are sensitive
to water motion-e.g., diffusion-weighted images

Front 169

A 45-year-old woman with diabetes mellitus and exercise claudication. Both
femoral pulses are markedly diminished, and the popliteal and pedal pulses are
detectable only by Doppler recording. The ankle/arm index (AAl) at rest was 0.48
on the right and 0.47 on the left.

Back 169

Leriche's syndrome: Symptoms include fatigue, symmetric
muscle atrophy, pallor of the lower extremities,
and impotence in males. Angiographically, these
patients frequently have an occlusion of the infrarenal
abdominal aorta.
+DIAGNOSIS: Bilateral aortoiliac atherosclerotic
disease.
+ KEY FACTS
CLINICAL
• In general, the diagnosis of claudication is a clinical
one based on history, physical examination, and noninvasive
testing. Physical examination findings include
diminished or absent peripheral arterial pulses pattern
and trophic changes in the affected extremities such as
hair loss and muscle atrophy. Nonvascular diagnoses
such as radiculopathy should be excluded before an
invasive procedure such as angiography.
• Obstructive atherosclerotic disease of the infrarenal
segment of the abdominal aorta and pelvic arteries
supplying the legs is relatively common, with a prevalence
of approximately 40/1 0,000 patients.
• Obstructive PVD is 5 to 10 times more common in men
than women. It generally occurs after 50 years of age
unless a concomitant disease such as diabetes mellitus or
a family history of atheromatous disease is present.
• The choice of therapies is determined by the anatomic
location and extent of arterial disease and comorbid
features (e.g., cardiopulmonary status). Approximately
90% of patients have a clinical history of occlusive
atheromatous disease in other locations---e.g., coronary
or carotid circulation.
• Integration of the history, physical examination, and
results of noninvasive tests allows preangiographic prediction
of the disease site and severity, including the
presence of inflow (i.e., suprainguinal) and ouflow
(i.e., infrainguinal) disease.
• The AAl in the resting state, which decreases as disease
severity increases, is used to quantitate disease severity.
Note that arterial disease of the upper extremities
could give a false-negative value. The following scale
correlates disease severity with AAl: normal: :?:0.9; mild
insufficiency: 0.7 to 0.9; moderate insufficiency: 0.5 to
0.7; severe insufficiency (i.e., a threatened limb): <0. 5 .
• Percutaneous transluminal angioplasty ( PTA), alone or
in combination with intravascular stenting, is the major
nonsurgical means of u·eating ad1C::fOmatous aortoiliac
disease. PTA is not possible when occlusive lesions
cannot be negotiated with a catheter-guidewire combination.
PTA is contraindicated when lesions are immediately
adjacent to arterial aneurysms.
351
• Aortobifemoral graft placement is generally reserved
fOf patients who have extensive atheromatous disease
and low surgical risk.
RADIOLOGIC
• Aortoiliac atl1eromatous disease frequently begins
above the aortic bifurcation and sometimes extends as
far as the distal iliac arteries. Alternatively, isolated
stenoses of each common iliac origin can occur. The
major aim of radiologic assessment is to determine preoperatively
the extent of disease (i.e., detect the presence
of either or both inflow and outflow disease),
which will guide therapy.
• Although PTA alone is frequently successful, intravascular
stenting is sometimes also necessary. Indications for stenting
include ( 1 ) a high residual aortoiliac systolic blood
pressure gradient ( > 1 5 mm Hg) or residual or recurrent
stenosis (>30%) after PTA, and (2) arterial dissection at
the angioplasty site that compromises blood flow.
• Factors that predict long-term patency after PTA can
be divided into two categories: ( 1 ) clinical predictors,
based on degree of ischemia as assessed by history and
physical examination; and (2) anatomic predictors,
based on lesion location (proximal versus distal) and
lesion appearance (stenosis versus occlusion; short,
concentric stenosis versus long, eccentric stenosis).
• Clinical predictors are based on the symptoms before
PTA. In general, patients who present with claudication
fare much better overall than those who present
for limb salvage (nonhealing ulcers, skin changes, hair
loss, etc.). This is not unexpected since the latter is a
reflection of much more extensive vascular disease.
• Anatomic predictors are based on the location and
angiographic appearance of the lesion. Proximal lesions
(so-called inflow disease) have a much better prognosis
than more distal lesions. Angiographic lesion appearance
refers to the degree of vessel narrowing, the degree of
irregularity of the lesion, and its length. In general,
patients with stenoses have a better result from PTA
than those wim occlusions, and patients wim short (i.e.,
<5 cm), concentric (smsmoom) lesions fare better man
mose wim long (i.e., >5 cm), eccentric (irregular)
lesions. Therefore, based on clinical and anatomic predictors,
the patient who complains onJy of claudication
and who has a short, smoom, proximal stenosis has me
best chance of long-term patency after PTA.

Front 170

A 1 2-year-old girl with a 6-year history of exertional dyspnea and palpitations.

Back 170

Left ventricular aneurysm: This entity might be considered,
because it can produce a left-sided contour
irregularity on chest radiographs. However, it is rare at
this age and is usually seen in the setting of left ventricular
infarction from coronary artery disease in older
adults. Furthermore, angiographic findings of an
aneurysm are not present.
• Idiopathic hypertrophic subaortic stenosis (IHSS):
IHSS is a consideration based on the history.
However, the chest radiograph in IHSS is often either
normal or shows diffuse cardiomegaly. The angiographic
findings are not consistent with this entity,
because in IHSS the ventriculoarterial relationships are
. normal and the ejection fraction is increased.
• Loculated pericardial effusion: The contour irregu-
1arity at the left heart margin makes this a diagnostic
consideration. However, the symptoms of palpitation
and chronic chest pain, as in the case shown above,
would be unusual. Furthermore, the angiogram would
be expected to be normal, unlike the findings in the
case presented.
• Partial absence of pericardium on the left: The history
is usual for this entity, because patients typically
present with acute, occasionally intermittent, chest
pain due to ischemia resulting from entrapment of the
herniated portion of the left atrium. However, there is
no irregularity of the left atrium on the angiogram
shown above.
• L-Ioop transposition of the great arteries: This
diagnosis is the most likely based on the history and
radiographic and angiographic findings.
+ DIAGNOSIS: L-Ioop transposition of the great
arteries (congenitally corrected transposition of the
great arteries).
+ KEY FACTS
CLINICAL
• The patient shown above represents the 1 0% of
patients with L-loop transposition of great arteries who
do not have evidence of associated cardiac defects.
353
• Over 90% of patients with L-loop transposition of the
great arteries will have or develop one or more of the
following lesions: ( 1 ) left-sided atrioventricular (AV)
(tricuspid) valve insufficiency, (2) heart block, ( 3 ) ventricular
septal defect (VSD), or (4) pulmonary stenosis.
• Because of the risk for later development of either or
both tricuspid insufficiency and heart block, patients
need close clinical monitoring.
RADIOLOGIC
• Absence of the normal triad of densities on the
frontal chest radiograph is explained on the following
anatomic abnormalities: ( 1 ) the ascending aorta is
left-sided, ( 2 ) the pulmonary trunk is more medial
and posterior, ( 3 ) the aortic knob is formed at a
more acute angle and is more medial on the posteroanterior
projection.
• Periodic radiographic evaluations are a helpful adjunct
to the clinical examination in the detection of associated
lesions. Interim development of left atrial and
right ventricular enlargement with either or both
cephalization of the pulmonary vasculature and pulmonary
edema are diagnostic signs of left-sided AV
valve insufficiency.
• Enlarging heart size in these patients can be seen in
the setting of heart block or AV valve insufficiency.
• Cardiomegaly and increased pulmonary vascularity
suggested an associated VSD .
• Decreased pulmonary vascularity i s suggestive o f pulmonary
stenosis only if a VSD is present.

Front 171

A 40-year-old woman with nephrotic syndrome and sudden onset of right-sided
pleuritic chest pain.

Back 171

The differential diagnosis on the chest radiograph is
that for any focal lung opacity and therefore includes a
wide spectrum of entities. However, given the unilateral
and focal nature of the pulmonary opacity, pneumonia
and lung infarct are the best considerations.
• The findings on the pulmonary angiogram are diagnostic
for acute pulmonary embolism ( PE).
+ DIAGNOSIS: Acute pulmonary embolus.
+ KEY FACTS
CLINICAL
• PE is a common, life-threatening entity with an estimated
600,000 cases per year in the United States
alone. Approximately 1 0% of the patients with PE do
not survive the initial event.
• The clinical signs of PE are nonspecific and typically
can include dyspnea, tachypnea, pleuritic pain, and
hemoptysis.
• Treatment usually consists of anticoagulation with
heparin followed by warfarin. If there is a contraindication
to anticoagulation, an inferior vena cava filter can
be placed at the time of angiography.
• Acute treatment of PE with thrombolytic agents has
not yet definitively demonstrated advantages over
long-term anticoagulation and is usually reserved for
very acutely ill patients to decrease their clot burden.
• Recurrent PE occurs in only a minority of patients
treated with anticoagulant therapy.
RADIOLOGIC
• Most patients with PE do have abnormal chest radiographs,
but the findings are nonspecific-e.g., either
or both atelectasis and pulmonary parenchymal opacities.
In the appropriate circumstances, however, it is
actually a normal radiograph that is most helpful in
assessment for PE. A normal chest radiograph in a
patient with dyspnea and hypoxia ( Pa02 ..70 mm Hg)
should strongly raise the possibility of PE, because it
effectively excludes other entities that clinically mimic
PE. The other main function of the chest radiograph is
to aid in interpretation of the ventilation-perfusion
imaging in a patient with suspected PE (see Chapter
1 0, Case 1 7 ) .
• Pulmonary angiography is usually performed using a
pigtail-type catheter placed from the common femoral
vein. Other access sites include the jugular and brachial
veins. Selective angiography is usually performed with
the catheter placed into the right or left pulmonary
artery. More subselective angiography can be performed
if there is concern regarding a specific region
of a lung.
• The contrast infusion for pulmonary angiography is
usually 1 5 to 25 m1/sec for a total of 30 to 50 ml in
each pulmonary artery, depending on arterial flow.
Filming is usually at three or four films per second.
355
• The presence of intra-arterial filling defects on pulmonary
angiography is indicative of PE. Complete
arterial occlusion (vessel cutoff) is also highly suggestive
of the diagnosis.
• Secondary signs of PE on pulmonary angiography
include parenchymal staining, decreased perfusion to
an area, crowding of vessels, delayed venous return
from the affected area, and vascular shunting away
from the involved lung.
• Pulmonary angiography currently remains the "gold
standard" technique for the diagnosis of PE. There
are, however, two main concerns with angiography:
( 1 ) reportedly high complication rates and (2) a substantial
degree of interobserver variability in study
interpretation.
• Initial concerns about performing pulmonary angiography
were for sudden death from cor pulmonale in
patients with elevated right heart (ventricular and pulmonary
artery) pressures. Pulmonary angiography was
considered contraindicated in patients with very high
right heart pressures, although a pressure above which
angiography would be contraindicated was never fully
defined. The risks of sudden death from pulmonary
angiography were placed at approximately 0.1%. This
probably was due to increased pulmonary artery pressures
following the injection of ionic contrast media in
patients with already elevated pressures and compromised
right heart function. In a review of 1 ,434 patients
from our instinltion using low-osmolar contrast agents,
no deaths from pulmonary angiography were incurred,
suggesting that nonionic contrast media are associated
with a relatively lower risk than ionic contrast media.
• Interobserver variability occurs mostly with smaller
thromboemboli, particularly those involving subsegmental
levels. When the emboli are large (as in Figure
7 -3B ) , the interobserver variability is very low.

Front 172

A 5 1 -year-old man with bright red blood per rectum.

Back 172

A meaningful differential diagnosis can only be generated
after the bleeding site is determined, which can be accomplished
by endoscopy (frequently lU1helpfi.tl when bleeding
is brisk) by nuclear medicine bleeding studies, or angiography.
The following is a differential diagnosis for hemorrhage
from a left colon bleeding site (as in the case shown):
• Diverticular hemorrhage: This cause is the most
common etiology of colorectal bleeding ( approximately
50% of cases). Diverticula occur more commonly
in the left colon, but those tllat occur in the
right colon carry tlle higher risk of bleeding • Angiodysplasia: Up to 20% of colorectal bleeding is
due to these acquired lesions. The angiographic
appearance is that of a small tuft of vessels with at least
one early draining vein. These findings are not seen in
tlle case illustrated.
• Neoplasm: Tumors account for about 1 0% of colorectal
bleeding. Tumor vascularity (not present in the case
shown) can sometimes be seen at angiography.
• Colitis: This entity accounts for 5% to 1 0% of cases of
colorectal bleeding. At angiography, prominent opacification
of involved segments of colon can often be
seen during the capillary phase ( not present in the
case shown).
+ DIAGNOSIS: Hemorrhage due to diverticular
disease in the descending colon.
+ KEY FACTS
CLINICAL
• Prompt and adequate hemodynamic stabilization (e.g.,
placement of large-bore intravenous lines and vascular
repletion) of the patient with gastrointestinal ( G I )
hemorrhage i s imperative before diagnostic procedures
are started.
• Eighty percent of patients with GI bleeding have
spontaneous resolution of the hemorrhage without
treatment.
• It is important to determine whether the source of
bleeding is from the upper ( i . e . , above the ligament of
Treitz) or lower GI tract. If gastric lavage contents are
clear, a source is presumed to be distal to the pylorus.
If the lavage contents are bile stained but without
overt evidence of hemorrhage, the source is most likely
in the lower GI tract.
• Upper or lower endoscopy will frequently identify the
bleeding source and provide the initial means of treatment,
including cautery, injection of epinephrine, or in
the case of variceal bleeding, sclerotherapy or banding.
• Substantial nonvariceal upper GI arterial bleeding not
responsive to endoscopic therapy is an indication for
emergency arteriography.
• When the source of lower GI bleeding cannot be
determined, a Tc-Iabeled red blood cell study, which
can detect bleeding at a rate of 0 . 1 ml/min, can be
performed to attempt to localize tlle bleeding site.
RADIOLOGIC
Upper Gastrointestinal Bleeding
• Angiography can only identify bleeding occurring at a
rate of 1 ml/min, a much faster rate than detectable
by tagged red blood cell studies. Extravasation of contrast
material into the bowel lumen is seen as pooling
of contrast material in the bowel lumen.
• Selective injections of the celiac, left gastric, gastroduodenal
( if the left gastric injection is negative), and
superior mesenteric arteries are performed routinely.
• Left gastric artery bleeding sites can be embolized with
gelatin sponge pledgets or metal coils because circulation
from the gastroepiploic, right gastric, and short
gastric arteries provides adequate collateral flow to prevent
infarction.
Lower Gastrointestinal Bleeding
• Sources of small bowel hemorrhage include ulceration,
diverticula, enteritis, neoplasm, angiodysplasia, and
aortoenteric fistula.

Front 173

A 52-year-old man 1 year status post placement of a left femoral-to-right femoral
artery bypass graft for right iliofemoral occlusion. The left femoral pulse is now
palpable, but the right femoral artery pulse and the graft pulse are nonpalpable.
The right leg is cooler than the left leg.

Back 173

DIFFERENTIAL DIAGNOSIS
• Acute left iliac artery thrombosis: This diagnosis
could account for the absence of pulses in the graft, but
the physical findings of a pulse in the left femoral artery
and the opacification of the left femoral artery during
angiography are not consistent with this diagnosis.
• Chronic right iliac artery occlusion and acute graft
thrombosis: This diagnosis adequately accounts for
the physical findings and the lack of opacification of
the graft prior to thrombolysis.
+DIAGNOSIS: Acute thrombosis of left femoralto-
right femoral graft.
+ KEY FACTS
CLINICAL
• The patency of femoral-femoral grafts is approximately
95% at 5 years. The most important factor is patency
of the superficial femoral artery. Failure of femoralfemoral
grafts is more often related to progression of
outflow (runoff) disease than to progression of inflow
(iliac) disease. Another cause of failure is stenosis at the
site of graft-arterial anastomosis.
• Femoral-femoral grafts are generally reserved for
patients who are at high risk for more extensive surgical
arterial reconstruction-e .g., aortofemoral grafting
procedures.
RADIOLOGIC
• Diagnostic angiography should be performed to define
the presence and extent of "inflow" or "outflow" disease
in patients being considered for thrombolytic
therapy.
359
• Thrombolytic therapy is a treatment option in patients
( 1 ) with viable extremities and ( 2 ) with threatened
extremities in whom the rate of progression of
ischemia would not preclude a prolonged ( 8 - to 24-
hour) thrombolytic infusion. Patients with irreversibly
ischemic extremities are not considered candidates for
thrombolytic therapy.
• To accomplish a successful thrombolytic infusion,
the entire length of the thrombosed graft must be
successfully negotiated with a catheter-guidewire
infusion syste m .
• Urokinase i s the agent o f choice i n most institutions. It
is usually administered as a bolus (typically a dose of
2 50,000 units) followed by low-dose ( 1 00,000 U/hr)
or high-dose (250,000 U Ihr) infusion of urokinase
into the graft. Serial angiograms are obtained to document
results. Infusion is terminated when thrombus is
successfully resolved, or when angiography shows no
improvement after a 4- to 8 -hour infusion.
• The interventionalist must attempt to identify and
treat the precipitating lesion responsible for causing
graft thrombosis. The treatable causes may be progression
of inflow disease (a stenosis proximal to the graft),
outflow disease ( a stenosis distal to the graft), or a
stenosis at the site of anastomosis.
+ SUGGESTED READING
McNamara TO. Thrombolysis Treatment for Acute Lower Limb
Ischemia. In D E Strandness Jr, A van Breda (eds), Vascular
Diseases: Surgical and Interventional Therapy. New York:
Churchill Livingstone, 1994;355-377.
Welch HJ, Belkin M. Acute Limb Ischemia Resulting from Graft
Failure. In DE Strandness Jr, A van Breda (eds), Vascular
Diseases: Surgical and Interventional Therapy. New York:
Churchill Livingstone, 1 994;379-392.

Front 174

A 69-year-old man who was struck in the chest during a motor vehicle accident.

Back 174

Aortic tear: The radiographic findings raise the strong
possibility of traumatic tear of the aorta and should
prompt the performance of a thoracic aortogram. The
abnormalities seen on the aortogram in this case are an
indication for emergency surgical repair.
• Mediastinal widening due to rupture of blood vessels
other than the aorta: The mediastinal widening in
the case illustrated could be due to laceration of other
blood vessels. However, this is a diagnosis of exclusion
that is reached only after angiography has determined
whether an aortic injury is present. In the case shown,
the angiogram does, in fact, show an aortic injury.
• Mediastinal widening due to causes other than
hematoma: Mediastinal widening can be caused by a
number of conditions other than trauma ( e . g . , lymphadenopathy,
aortic tortuosity). When relatively
recent previous radiographs that show an abnormal
mediastinal contour are available, such non traumatic
causes should be considered.
+ DIAGNOSIS: Traumatic tear of the thoracic
aorta at the isthmus.
+ KEY FACTS
CLINICAL
• Only 1 0% to 20% of patients with traumatic rupture of
the aorta survive long enough to come to a hospital.
Of those patients who survive long enough to receive
medical care, there is a 95% to 97% mortality rate if
the aortic rupture is untreated.
• Based on autopsy series, about half of aortic tears are
located at the isthmus (distal to the left subclavian artery
and proximal to the third intercostal artery). This is the
site at which the ligamentum arteriosum attaches the
aorta to the left pulmonary artery. The isthmus is the
site of aortic laceration in the vast majority (90% to
95%) of patients who survive to reach the hospital.
• About 20% of aortic lacerations involve the ascending
aorta. Laceration at this site is nearly always fatal. Less
commonly involved sites are the distal thoracic,
diaphragmatic, and abdominal aortic segments.
• Multiple tears are seen in 1 5 % to 20% of cases.
• Clinical signs of aortic injury include hypertension in
the upper extremities, diminished blood pressure in
the lower extremities, and bruits.
• There are several theories for the etiology of aortic
tear/transection. One widely accepted hypothesis is
that a deceleration injury produces shear and stress at
points of maximal fixation of the aorta.
• Emergency surgical repair, usually by placement of a
prosthetic aortic graft, is typically indicated. Primary
repair ( i . e . , suturing of the laceration) and patch
angioplasty are other, less frequently used, procedures.
361
RADIOLOGIC
• No single radiographic sign is pathognomonic of aortic
rupture. However, a number of chest radiographic findings
should strongly raise suspicion of an aortic tear in
a trauma patient and should prompt aortography.
These include: ( 1 ) widened mediastinum, ( 2 ) depressed
left mains tern bronchus, ( 3 ) deviation of the esophagus
(deviated nasogastric tube) and trachea at the level of
the T4 vertebral body, (4) obscured margins of the aortic
arch, ( 5 ) left apical opacity ( "apical cap"), ( 6 ) fracture
of any of the first three ribs, (7) widening of a
paraspinal line, and ( 8 ) widening of the right paratracheal
stripe .
• Aortography is usually performed by a transfemoral
approach . However, if femoral artery blood pressures
are diminished (alone, or in combination with elevated
blood pressure in the arms), a brachial artery puncture
should be used, because a post-traumatic coarctation
may present.
• Aortography remains the gold standard for diagnosis.
During aortography, an injection in the left anterior
oblique projection should be performed first, followed
by a right anterior oblique or lateral projection. The
brachiocephalic vessels and region of the descending
aorta above the celiac artery should be included in the
field of view. An aortic laceration can be missed if only
a single projection is used at aortography.
• Most patients develop a pseudoaneurysm at the site of
laceration. An intimal tear alone is present in 5% to 1 0%
of cases, seen as a linear lucency on the angiogram.
• Causes of false-positive aortograms, seen in 1 % of cases,
include ductus diverticulum, aortic aneurysm, atherosclerotic
plaque, aortic dissection, and artifacts due to
inflow of unopacified blood ( i . e . , "streaming" artifacts ) .
• Helical C T of the thoracic aorta i s being investigated
as a noninvasive means of diagnosis of thoracic aortic
injury and has been reported to have 1 00% sensitivity
and 82% specificity. Possible limitations include inadequate
evaluation of the ascending aorta ( due to cardiac
motion artifact

Front 175

A 58-year-old woman with substernal pleuritic chest pain and new dyspnea on
exertion. She subsequently experienced an episode of transient hemiplegia following
infusion of an intravenous catheter with saline.

Back 175

More than 95% of all single pulmonary nodules fall into
one of the ftrst three categories discussed below.
• Benign tumor: A noncakifted, lobulated, well-circumscribed
lesion in the periphery of the lung is most
likely to represent a hamartoma. Characteristic "popcorn"
calciftcations and presence of internal fat on CT
would strongly support this cliagnosis. However, the
curvilinear structure on the chest radiograph would be
atypical, and the MR and pulmonary angiography ftndings
are not consistent with this diagnosis.
• Granuloma: The upper lobe location, well-circumscribed
margins, and stability over time may suggest
tuberculous or fungal disease . The size and conftguration
of the lesion seen on the chest radiograph would
be unusual for granulomatous disease. Furthermore,
the MR and angiography findings are not consistent
with this diagnosis.
• Neoplasm: The stability over time and well-circumscribed
margins on the chest radiograph strongly argue
against malignancy. As in the case of the other diagnoses
previously mentioned, the MR study and the pulmonary
angiogram are not consistent with this diagnosis.
• Pulmonary arteriovenous malformation (AVM):
The curvilinear opacity seen on the chest radiograph is
compatible with the draining vein of an AVM . The
presence of flow in multiple enlarged vessels on the
gradient echo MRl also suggests an AVM . The diagnosis
is definitively established on the pulmonary
angiogram that shows enlarged feeding arteries, a vascular
nidus, and draining veins.
+ DIAGNOSIS: Pulmonary arteriovenous
malformation.
+ KEY FACTS
CLINICAL
• Pulmonary AVMs ( also called, perhaps more accurately,
AV ftstulas) can present with hemoptysis, chest
pain, hypoxia, and neurologic symptoms (including
stroke, transient ischemic attacks, and cerebral abscess
formation) from paradoxical emboli.
• Clinical signs include clubbing, cyanosis, polycythemia,
chest bruit, and evidence of paradoxical emboli.
• Pulmonary AVMs are usually congenital lesions,
although they have been associated with trauma, infection,
and prior surgery.
• Pulmonary AVMs are rarely symptomatic if <2 cm in
size. Many investigators maintain that o·eatm.ent is war-
363
ranted even for asymptomatic lesions <2 cm in size or
those having a feeding vessel of ..3 mm. Increasingly,
endovascular therapy using coil or balloon occlusion,
rather than surgical ablation, is the treatment of choice.
• The most important clinical association is with hereditary
hemorrhagic telangiectasia ( HHT) ( Osler-WeberRendu
syndrome ) . HHT is autosomal dominant with
variable penetrance and is characteristically associated
with the triad of epistaxis, telangiectasias, and family
history of the syndrome. It is estimated that at least
one-third of patients with pulmonary AVMs have
HHT. However, only approximately 1 5% of patients
with HHT have pulmonary AVMs.
RADIOLOGIC
• More than 95% of patients with pulmonary AVMs
have an abnormal chest radiograph .
• Pulmonary AVMs can b e c1assifted a s simple ( i . e . , having
a single feeding vessel and single draining vein,
which is seen in 80% of cases) or complex (i.e., having
two or more feeding and/or draining vessels) .
• Approximately two-thirds o f pulmonary AVMs are
solitary lesions.
• Approximately two-thirds of pulmonary AVMs are
located in the lower lobes.
• High-resolution CT, MRl, and MRA have shown utility
in cliagnosis of these lesions.
• Renal and cerebral radiotracer activity during lung perfusion
study is a characteristic finding that can be seen
due to the right-to-left shunting resulting from pulmonary
AVMs. The presence of these findings during
a lung perfusion study is a clue to the diagnosis of pulmonary
AVM .
• Pulmonary angiography can confirm the diagnosis,
classifY the type of lesion, and provide the means for
endovascular treatment. Permanent occlusion with
coils or detachable balloons has a high success rate,
with low morbidity and low mortality. The main risk is
systemic embolization of coil or balloon during
deployment, which ismore likely in simple AVMs than
in complex AVMs.

Front 176

A 36-year-old man with fever, hematuria, and elevated sedimentation rate. He has a
history of hepatitis B infection.

Back 176

Polyarteritis nodosa (PAN): PAN is a necrotizing
vasculitis of unknown etiology, which has been associated
with prior hepatitis B virus infection. The typical
findings consist of multiple small aneurysms in the
renal and other abdominal arterial circulation . The
clinical history and angiographic findings in the case
illustrated make this the most likely diagnosis.
• Vasculitis of intravenous drug abuse: This entity is
also a necrotizing vasculitis, which can have an identical
angiographic appearance to PAN. The absence of a
history of drug abuse favors an alternative diagnosis,
although it must be kept in mind that such a history is
often not revealed by the patient.
• Vasculitis associated with connective tissue disorders:
These include a number of connective tissue disorders
(e.g., systemic lupus erythematosus, rheumatoid
arthritis, and Sjogren's syndrome ) that have an angiographic
appearance similar to the findings in the case
illustrated. The diagnosis is based on clinical and serologic
tests and is typically known by the time angiography
is performed.
+ DIAGNOSIS: Polyarteritis nodosa.
+ KEY FACTS
CLINICAL
• PAN is an immune complex-mediated necrotizing vasculitis
affecting multiple organ systems.
• A 3 to 1 male-to-female predominance has been
reported.
• PAN can be seen at any age, but the peak incidence is
in the fourth and fifth decades.
• The clinical symptoms reflect the multisystem involvement
and include fever, weight loss, weakness, and
malaise. The remainder of symptoms are organ system-
specific and vary considerably among patients.
• Laboratory findings include elevated erythrocyte sedimentation
rate, anemia, and elevated white blood cell
count. Rheumatoid factor is present in many patients,
and evidence of previous hepatitis B infection is seen in
1 5%. Elevated circulating immune complexes and
hypocomplimentemia strongly suggest the diagnosis.
• Renal involvement, often manifested by rapidly progressive
renal failure and hypertension, is present in
75% to 85% of PAN patients. Renal abnormalities can
include a necrotizing glomerulonephritis, vasculitis,
and small renal artery aneurysms.
365
• Neurologic involvement is common but is usually confined
to one or more peripheral or cranial nerves. Less
commonly, the brain or spinal cord is involved by
infarction or hemorrhage.
• Gastrointestinal ( G I ) involvement is seen in 50% of
patients and may involve any organ in the GI system .
Bowel ischemia and perforation secondary to necrotizing
vasculitis can be life-threatening.
• Cardiac involvement, including congestive heart failure,
myocardial infarction, and pericarditis, is seen in
80% of patients.
• Musculoskeletal involvement, including myalgias and a
polyarthritis that is clinically similar to rheumatoid
arthritis, is also relatively common.
• Untreated, the 5 -year survival rate is 1 0% to 1 5%, with
death commonly resulting from hypertension-related
complications, cardiac involvement, or complications
due to infarction of one or more organs. Treatment
with high-dose corticosteroids and cyclophosphamide
has resulted in 5 -year survival rates of 80%.
RADIOLOGIC
• Abnormal renal angiograms are seen in 70% to 80% of
PAN patients, usually involving small- and mediumsized
arteries, often within intrarenal branches. The
major findings (many of which are the result of necrosis
and inflammation) include small aneurysms at bifurcations,
segmental narrowing or dilation ( due to loss
of vasomotor control), and arterial occlusions ( due to
a necrotizing, inflammatory process).
• I nvolvement of the mesenteric arteries occurs in 65%
of PAN patients. The findings are generally similar to
those seen in the renal arteries.
• Appropriate assessment of PAN patients by angiography
includes selective renal, celiac, and superior mesenteric
injections.

Front 177

A 27-year-old woman with a painful mass in the posterior aspect of the distal left
thigh. The mass was associated with a thrill and bruit.

Back 177

DIFFERENTIAL DIAGNOSIS
• Arteriovenous (AV) fistula: An AV fistula consists of
a direct communication of a large, identifiable artery
draining directly into a vein, without an intervening
retiform plexus (nidus). Fistulas can be single (one
artery-one vein) or multiple. This diagnosis is incorrect
because a nidus is clearly identified in the case
illustrated.
• Hemangioma: This diagnosis is incorrrect because
hemangiomas typically appear at angiography as a vascular
blush without large feeding arteries or draining
veins. However, the lesion in the case illustrated has
the appearance of a tangle of vessels ( nidus) with discrete
feeding arteries and draining veins.
• Peripheral arteriovenous malformation (AVM):
This diagnosis is correct because the lesion shown
above has all of the features of an AVM, which are
outlined in Case 7.
+ DIAGNOSIS: Peripheral arteriovenous
malformation.
+ KEY FACTS
CLINICAL
• Peripheral AVMs are congenital and are presumed to
represent a focal persistence of primitive vascular elements
that arise in the first trimester of gestation.
Rarely, AVMs are genetic in nature.
• AVMs within extremities can have a clinical presentation
of a cosmetic deformity, pulsatile mass, or painful
lesion. Very large AVMs can produce high-output cardiac
failure due to AV shunting. However, AVMs are
frequently stable lesions that require no specific therapy.
• Some AVMs aggressively expand, necessitating treatment.
The primary mechanism of expansion is by
367
enlargment of existing channels and recruitment of new
collateral vessels, rather than by cellular proliferation.
RADIOLOGIC
• AVMs are generally fed by more than one artery.
Peripheral AVMs can have a variable degree of capillary
blush.
• Large AVMs can contain one or more fistulous sites.
• The extent of AVMs can be well defined by crosssectional
imaging studies such as CT, MRI, and MRA,
but dynamic flow patterns are best seen on catheter
angiography.
• AVMs are frequently treated by transcatheter
embolization, alone or in conjunction with surgery.
On occasion, AVMs are treated by surgery alone, especially
when only one or a few feeding arteries, which
are directly accessible to surgery, are present.
• Transcatheter embolization can be performed using a
number of embolic agents. Polyvinyl alcohol particles
are frequently used because, depending on the size of
the particles chosen, they can be directly deposited
within the nidus. Embolization of the arteries feeding
the AVM is an undesirable result because it can result
in the recruitment of secondary arterial supply to the
AVM, necessitating repeat treatments. Furthermore,
occlusion of feeding arteries can hamper subsequent
efforts at embolization by blocking access of embolic
agents to the nidus.
+ SUGGESTED READING
Riles TS, Rosen RJ. Arteriovenous Fistulae. In DE Strandness Jr, A
van Breda (eds), Vascular Diseases: Surgical and Interventional
Therapy. New York: Churchill Livingstone, 1 994; 1 1 09-1 1 1 4 .
Rosen RJ, Riles T S . Arteriovenous Malformations. I n DE Strandness
Jr, A van Breda (eds), Vascular Diseases: Surgical and
Interventional Therapy. New York: Churchill Livingstone,
1 994; 1 1 2 1-1 1 37.

Front 178

An I 8-year-old woman with exertional dyspnea with chest pain for 1 8 months

Back 178

Secundum atrial septal defect (ASD): Right ventricular
enlargement is a feature of an ASD . However,
the increase in pulmonary vascularity should be diffuse
and symmetric ( unlike the cases shown ), making
this an unlikely diagnosis.
• Right pulmonary artery hypoplasia: This entity
might be considered because of the discrepancy in pulmonary
blood flow between the two lungs. However,
this diagnosis is unlikely because the right lung is
almost always hypoplastic in this disorder, whereas the
right lung is normal in the above examples.
• Pulmonary embolism: This entity can produce asymmetric
pulmonary blood flow. However, no emboli are
evident on the angiogram.
• Pulmonary artery aneurysm: This very rare entity
can produce a prominent shadow at the confluence of
the pulmonary arteries. However, it is an unlikely diagnosis
in this case, because the pulmonary blood flow is
symmetric in this condition.
• Pulmonary hypertension: This entity might be a consideration,
because in severe cases the right side of the
heart is enlarged (in accordance with the fmdings in
Figure 7- 1 0A ) . However, symmetric prominence of
the central pulmonary arteries with climinutive flow
peripherally would be seen, unlike the asymmetric vascularity
seen in the cases shown above .
• Valvular pulmonary stenosis: Asymmetric pulmonary
blood flow and enlargement of the right ventricle are
the hallmarks of this entity and make it the most likely
diagnosis.
+ DIAGNOSIS: Valvular pulmonary stenosis.
+ KEY FACTS
CLINICAL
• Valvular pulmonary stenosis is a relatively common
congenital heart disorder. Dyspnea and fatigue are
the most common symptoms. The size of the valve
orifice in cases of mild to moderate stenosis tends to
increase as the patient grows, allowing survival into
adulthood.
• A loud ejection systolic murmur heard at the upper left
sternal border is typical. Electrocardiogram ( ECG)
findings indicate right ventricular hypertrophy and
right axis deviation . Cardiac catheterization shows
valvular pulmonary stenosis with a systolic pressure
gradient across the pulmonic valve .
369
• A similar ejection systolic murmur in the pulmonary
area and ECG evidence of right ventricular hypertrophy
can be seen with a secundum ASD . A fixed, splitsecond
heart sound is typical of an ASD, although not
invariably present. The two entities are distinguishable
by imaging findings (see below).
• Echocardiography is usually diagnostic, obviating the
need for an invasive procedure such as catheterization.
However, catherization is performed for diagnostic
purposes when the clinical data and echocardiographic
findings are discrepant or, in some cases, for therapeutic
purposes-e .g., if balloon angioplasty to improve
blood flow across the stenotic valve is a consideration.
RADIOLOGIC
• The characteristic radiographic findings of valvular pulmonary
stenosis can be explained on the basis of the
abnormal hemodynamics.
a. During systole, the high pressure within the right
ventricle is converted into high-velocity flow, creating
a forceful jet in the direction of the left pulmonary
artery. Dilatation of the main and left
pulmonary artery results.
b. A low-pressure zone can be created immediately
lateral to the central axis of the jet stream. Such
reduced pressure has a suction effect, facilitating
the leftward flow at the expense of right pulmonary
flow. The resultant abnormal flow pattern
can be shown by chest radiographs, pulmonary
angiograms, or perfusion lung scan.
• Successful valvulotomy is usually followed promptly by
a reversion to the normal flow pattern.
• The above-mentioned left lateralized pulmonary blood
flow pattern of valvular pulmonary stenosis is distinctly
different from the bilateral symmetrical increase in pulmonary
vascularity seen in secundum ASD .

Front 179

Two patients with hypertension: patient A, shown in Figure 7 - I IA, is a 67-year-old
man with an abdominal bruit; patient B, shown in Figure 7 - l I B, is a 37-year-old
woman with hypertension of recent onset.

Back 179

Patient A: The findings are typical of atherosclerotic
renovascular disease, with a smoothly tapered contour of
the stenotic lesion located near the origin of the artery.
• Patient B: The multilobulated, "beaded" appearance
and the fact that the distal main renal artery is involved (rather than the orifice ) is typical of fibromuscular
dysplasia. Neurofibromatosis is another rare
entity that could also produce the same appearance.
However, neurofibromatosis would be expected to be
associated with other clinical ( e .g . , cutaneous manifestations)
or radiologic findings, which are not present
in the case illustrated.
DIAGNOSES: Atherosclerotic renal artery disease
(patient A) and fibromuscular renal artery disease
(patient B).
+ KEY FACTS
CLINICAL
• The symptomatic clinical presentation of renal artery
stenosis is hypertension, renal failure, or both. The
emphasis in this discussion is on hypertension.
• Approximately 60 million Americans are affected by
hypertension. Renovascular hypertension, however,
accounts for only a small minority « 5%).
• Indications that hypertension may be renovascular in
nature include ( 1 ) presence of an abdominal or flank
bruit (due to renal artery stenosis), ( 2 ) increase in
serum creatinine levels by 0 . 5 mg/dl or more following
antihypertensive treatment with angiotensinconverting
enzyme (ACE) inhibitor therapy, and
( 3 ) malignant hypertension (i .e., hypertension that is
rapid in onset and refractory to medical therapy) .
• The diagnosis of renal artery stenosis i s then made by
radiographic techniques, including nuclear scintigraphy
and angiography. Angiography remains the gold standard
and has the advantage of visualizing the arteries
and permits treatment (i.e., percutaneous transluminal
angioplasty [ PTA] ) during the sanle exanlination.
Nuclear scintigraphy does not directly visualize the renal
arteries but can determine relative perfusion as well as
renal function. Other techniques to visualize the renal
arteries include CT angiography, MRA, and sonography.
• PTA has become tlle initial treatment of choice in
many patients with renovascular hypertension, especially
those with hypertension refractory to medical
therapy. In particular, PTA has become the treatment
of choice for fibromuscular disease.
RADIOLOGIC
• Renal artery stenosis is considered hemodynamically
significant when tllere is ..75% narrowing of the crosssectional
area of the lumen.
• In performing renal PTA, it is important to choose the
appropriate balloon size. Careful measurements of the
"normal" arterial lumen should be made before balloon
insertion. When measurements are made from
angiograms performed using conventional film-screen
tecluuques, a magnification factor of 1 0% to 20% can be
assumed. It is generally considered acceptable to overdilate
the artery by that degree. Measurement programs are
available to measure tlle size of the artery when angiography
is performed using digital subtraction technique. In
this setting, overdilation by 20% is again acceptable.
• During renal PTA, guidewires and catheters should be
passed across stenoses carefully and pressures obtained
on each side of a stenosis. A1tllOugh controversy exists
about exact values, pressure gradients of > 1 0 mm Hg
systolic are generally considered abnormal .
• Renal PTA is usually performed after the patient is
fully anticoagulated. After placement of the baLloontipped catheter across the stenosis and dilatation with
the balloon, repeat angiography is performed while the
guidewire is traversing the stenosis.
• If tlle angioplasty result is radiographically acceptable
(e.g., d O% residual stenosis ) , follow-up pressures can
be obtained and the procedure discontinued.
• There are multiple reasons for treatment failure (as defined
by a poor angiographic result) . Treatment of unwanted
results must be considered on an individual basis and is
often decided by a multidisciplinary team of an internal
medicine physician, a surgeon, and the interventional
radiologist. Possible undesired outcomes include:
a. The stenosis is still present. Treatment then often
consists of use of either or both a larger balloon
and placement of a stent.
b. A large intimal dissection has resulted. This complication
is usually treated by stent placement.
c. Extravasation of contrast material is seen. In this
circumstance, typically the balloon is reinflated to
occlude the site of extravasation and emergency
surgical repair is performed.

Front 180

A 7-month-old with respiratory distress and stridor.

Back 180

DIFFERENTIAL DIAGNOSIS
• Right arch with aberrant left subclavian artery: This
entity might be considered because a vascular channel is
seen coursing to the right of the trachea in the images
shown above . However, a left aortic arch is also clearly
delineated, making this an incorrect diagnosis.
• Double aortic arch: This entity frequently causes tracheal
stenosis of the type shown above. In the case illustrated,
two vascular channels are clearly seen, one on
each side of the trachea. This is the correct diagnosis.
• DIAGNOSIS: Double aortic arch.
KEY FACTS
CLINICAL
• The double aortic arch results from a persistence of
tlle theoretical embryologic double arch. The double
arch courses on both sides of the trachea and fuses
posteriorly to form the descending aorta, which usually
descends to the left of the spine. The right component
of the double arch is usually larger and more cephalad
than tlle left component. Separate great vessels ( a
carotid and a subclavian artery) arise from each arch. A
separate ductus arteriosus also arises from each arch,
but the right ductus arteriosus is usually atretic.
• The double aortic arch usually results in a tight vascular
ring which produces upper airway obstruction and
dysphagia in early life . This condition requires immediate
surgical intervention .
373
• The most common type of double aortic arch is seen
in the case shown above, with two patent arches (type
I double aortic arch) . In the type II double aortic
arch, tl1e left aortic arch is atretic.
• Another form of vascular ring is tllat of a right aortic
arch witll an aberrant left subclavian artery. This entity
is a more common anomaly than the double aortic
arch, but tlle vascular ring in tlle right aortic arch with
an aberrant left subclavian artery is usually loose and
less frequently requires surgical repair.
RADIOLOGIC
• The diagnosis of double aortic arch can readily be
made on MRI . Coronal and axial spin echo MRIs are
usually necessary to confirm the diagnosis.
• Coronal MRIs best show the presence of two aortic
arches and the more cephalad relation of the right arch
relative to the dominant left arch.
• Images in the axial plane best show esophageal and
tracheal compression secondary to the presence of the
double aortic arch.
• SUGGESTED READING
Gomes AS, Lois JF, George B, et al. Congenital abnormalities of the
aortic arch: MR imaging. Ractiology 1 987; 1 65 :69 1 -69 5 .
Link KM. Carctiovascular MR Imaging: Present Status. Radiology
Syllabus. Chicago: Radiological Society of North America, 1 990.
Stewart JR, Kincaid OW, Edwards JG. An Atlas of Vascular Rings
and Related Malformations of the Aortic Arch System .
Springfield, IL: Charles C . Thomas, 1964.

Front 181

A 19-year-old physically active man with a history of progressively increasing intermittent
claudication involving only the right calf. There was no history of trauma.
The right femoral pulse is normal, but the right popliteal and pedal pulses were present
only by Doppler examination.

Back 181

DIFFERENTIAL DIAGNOSIS
• Atherosclerotic occlusion: An atherosclerotic
popliteal occlusion is unlikely in the patient shown
above on the basis of age alone. Atherosclerotic occlusions
are much more common in older men and more
common at Hunter's canal (adductor canal) than at
the popliteal level.
• Thrombosed popliteal aneurysm: The typical features
of popliteal aneurysms are one or more of the following
features: claudication (present in the case described
above), acute thrombosis, and embolization from the
aneurysm. However, popliteal aneurysms are more
common with advancing age and would be unusual in a
young patient, making this an unlikely diagnosis.
• Popliteal artery occlusion secondary to popliteal
entrapment syndrome: The young age of the patient
shown above, history of vigorous physical activity,
presence of claudication, and occlusion of the artery
at the level of the popliteal fossa make this the most
likely diagnosis.
DIAGNOSIS: Popliteal artery entrapment
syndrome.
KEY FACTS
CLINICAL
• Popliteal artery entrapment syndrome is characteristically
seen in young athletes with unilateral or bilateral
claudication and is seen more commonly in men .
375
• Classifications of this syndrome are based on the relationship
of the popliteal artery to the gastrocnemius
muscle attachment to the femur.
• The pulses in patients with this syndrome can be normal,
diminished, or absent. Typically, plantar flexion of
the foot will diminish or obliterate the pulses.
RADIOLOGIC
• Some degree of medial deviation of the popliteal artery
is typically seen at angiography in patients with this
syndrome. If the popliteal artery is patent with the leg
in the neutral position, provocative (stress) angiography
during plantar flexion of the foot will typically
show narrowing or occlusion of the artery.
• Angiography can show a stenosis or occlusion when
the pulses are diminished or absent, respectively. The
occlusion may be chronic on both clinical and angiographic
grounds.
• SUGGESTED READING
Collins PS, McDonald PT, Lim RC. Popliteal artery entrapment: An
evolving syndrome. J Vasc Surg 1989;1 0:484-489.
Greenwood LH, Hallett JW, Yrizarry JM, et al. The angiographic
evaluation of lower extremity arterial disease in the young adult.
Cardiovasc Intervent Radiol 1985;8 : 1 8 3-186.
Persky JM, Kempczinski RF, Fowl RJ. Entrapment of the popliteal
artery. Surg Gynecol Obstet 1 99 1 ; 1 7 3 : 84-90.

Front 182

A I S-year-old boy with easy fatiguability, exertional dyspnea, cyanosis, and intermittent
chest pain of 4 years' duration.

Back 182

Isolated pulmonary atresia (without a VSD): The
markedly enlarged heart raises this entity as a possible
diagnosis. However, without benefit of surgery,
patients usually succumb in infancy. The pulmonary
outflow tract is also patent in the case shown and
would not be expected in pulmonary atresia.
• Tetralogy of Fallot (TOF): Despite the similarity of
pulmonary oligemia and clinical cyanosis in both entities,
the heart in patients with TOF would not attain
the size shown above because of the presence of a
large VSD (a pathway for blood flow when the pulmonary
outflow tract is obstructed) . Furthermore, the
aorta would be expected to be much larger due to the
large right-to-left shunt across the VSD found in
patients with TOF.
• Cardiomyopathy: Heart enlargement of the degree
shown above can be seen \vith cardiomyopathy.
However, the pulmonary blood flow would not be
expected to be diminished.
• Pericardial effusion: This entity can produce
marked cardiomegaly. Large effusions are usually
chronic. However, in the case of pericardial effusion,
the angiogram would be expected to be normal
other than for the presence of an opacity separating
the myocardium from the lung ( representing the
pericardial fluid).
• Ebstein's anomaly: This is the best diagnosis based
on the large right heart and displacement of the tricuspid
valve into the right ventricle ( "atrialization of the
right ventricle" ) .
DIAGNOSIS: Ebstein's anomaly (with severe tricuspid
insufficiency and right-to-Ieft shunt across
the atrial septum).
+ KEY FACTS
CLINICAL
• Ebstein's anomaly can present in the newborn period
(\vith cyanosis and marked cardiomegaly) or later in
childhood, usually \vith cyanosis, dyspnea, chest pain,
or arrhythmias.
377
• Typically, a harsh holosystolic murmur of tricuspid
regurgitation is heard at the left lower sternal border.
The ECG shows right axis deviation. Cardiac conduction
disturbances can also be evident.
• Severe tricuspid insufficiency is typically present. The
posterior and septal leaflets of the tricuspid valve are displaced
into the right ventricle, \vith atrialization of a portion
of the right ventricle. A right-to-left shunt across an
ASD or patent foramen ovale can often be seen.
• Standard surgical repair involves replacement of the tricuspid
valve, plication of the atrialized right ventricle,
and closure of an ASD .
RADIOLOGIC
• The radiographic findings in Ebstein's anomaly are
highly suggestive of the diagnosis, which can often be
established definitively by echocardiography.
• Gross enlargement of the right ventricle and the
right atrium is typical for Ebstein's anomaly because
severe tricuspid insufficiency causes considerable
right-sided volume overload without a runoff at the
ventricular leve l .
• Pulmonary oligemia i s caused by ( 1 ) marked decrease
in forward pulmonary blood flow, ( 2 ) severe tricuspid
insufficiency, and ( 3 ) right-to-left shunting across the
atrial septum.
• The principal alternative diagnosis to be considered
based on the typical clinical and radiographic findings
is pulmonary atresia without a VSD.
• Cardiomyopathy and pericardial effusion can also give
marked cardiomegaly, but without the decreased pulmonary
blood flow present in Ebstein's anomaly.

Front 183

A 5 5-year-old patient status post motor vehicle accident in which he was ejected
from the car.

Back 183

DeBakey type I aortic dissection: This category of
dissection involves both the ascending aorta and
descending aorta. This is the correct diagnosis.
• DeBakey type II aortic dissection: This form of dissection
is localized to the ascending aorta and rarely seen at angiography. The descending aorta is clearly
involved in the case illustrated, making this an incorrect
diagnosis.
• DeBakey type III aortic dissection: This form of dissection
involves only the descending aorta.
DIAGNOSIS: Thoracic aortic dissection,
DeBakey type I .
KEY FACTS
CLINICAL
• Predisposing factors include hypertension (the main
risk factor), pregnancy, collagen vascular disease (e.g. ,
Marfan's syndrome ), bicuspid aortic valves, aortic
coarctation, mycotic aneurysm, and giant cell arteritis.
• The typical presentation is severe chest or back pain
(seen in 90%) radiating into the neck, arms,
abdomen, or hips. End -organ ischemia such as infarction
of the brain or heart can occur when arteries
arising from the aorta (e.g., carotid or coronary
arteries) are compromised.
• Physical findings can include hypertension ( 70% of
cases), murmur of aortic insufficiency (due to extension
of the dissection to involve the aortic valve), and asymmetric
pulses between upper and lower extremities.
• Two schemes used for classification are the Stanford and
DeBakey types. Stanford type A includes any dissection
involving the ascending aorta; Stanford type B includes
all dissections begimling distal to the left subclavian
artery. The DeBakey classification is outlined above in
the Differential Diagnosis section. Rates for each type
are: type I : 5 1%; type I I : 6%; and type I I I : 43%.
• Stanford type A dissections are treated surgically, with
replacement of the ascending aorta and, if necessary, the
aortic valve. The goal is to prevent dissection of the aortic
root and rupture into the pericardium. Stanford type
B dissections are repaired when arterial branches are
compromised or progressive enlargement of the false
lumen to >6 cm occurs. Aggressive control of hypertension
is critical to prevent extension of the dissection.
• Involvement of major branch vessels should be defined
preoperatively by CT or angiography. Surgical repair
consists of placement of a mural graft replacement at
the site of the intimal tear and obliteration of the false
lumen by suturing, taking care to not occlude major
arteries arising from the false lumen.
RADIOLOGIC
• Twenty-five percent of patients with aortic dissection
have normal chest radiographs. Mediastinal widening is
the most helpful finding, especially if the mediastinum
appeared normal on a previous radiograph. Internal
displacement of aortic calcifications from the periphery
of the aorta is another finding that should raise suspicion
of aortic dissection.
• Aortic arch arteriography provides the most detailed
information of available diagnostic studies. Features to
be evaluated on angiography include:
a. The true lumen is typically contrast-filled and
narrowed due to compression by the false lumen.
b. The false lumen is also contrast-filled if not
thrombosed. The diameter of the false lumen can
vary from very thin to a thickness substantially
exceeding that of the true lumen .
379
c. The intimal flap is seen as a lucency separating
the true and false lumens. If the false lumen is
thrombosed, the intimal flap represents the wall
of the true lumen closest to the thrombus.
d. The entry/exit points are seen as contrast-filled
sites of commw1ication between the true and
false lumens. However, exit and entry points are
not always present, as when the dissection occurs
due to hypertension-related hemorrhage into the
vasa vasorum.
e . Other features to be evaluated include integrity of
the coronary arteries and the aortic valve .
• False-negative angiograms can occur due to ( 1 ) small,
focal dissections near the aortic root; ( 2 ) a small, thrombosed
false lumen that does not appreciably narrow the
true lumen; or ( 3 ) simultaneous opacification of both
lumens in which the intimal flap is not apparent.
• CT is the most commonly used screening study for the
evaluation of possible aortic dissection. As with angiography,
the presence of true and false cham1els separated by
an intimal flap is necessary to make the diagnosis.
Secondary signs include clotted blood in a false channel,
inward displacement of aortic wall calcifications, and
compression of the true lW11en. CT can also show pericardial,
pleural, and mediastinal hemorrhage, all of which
indicate arterial rupture. LinUtations of CT include

Front 184

A 67-year-old manual laborer with left arm cramping after exercise and gradual
onset of dizziness.

Back 184

DIFFERENTIAL DIAGNOSIS
• The etiology of the left subclavian artery occlusion is
most likely atherosclerotic disease, particularly given
the disease in the other great vessels.
• Other reasons for great vessel occlusion include
trauma, arteritis (including Takayasu's and radiation
therapy), and neurofibromatosis. Because a clinical history
of trauma is not given, this is not Likely to be the
diagnosis in the case shown above. Arteritis and neurofibromatosis
usually have the angiographic appearance
of smooth, concentric arterial narrowing rather
than the abrupt occlusion shown above. Furthermore,
the presence of mild changes typical of atheromatous
disease in other arteries makes these diagnoses unlikely.
+DIAGNOSIS: Left subclavian artery stenosis with
retrograde flow in the left vertebral artery ("subclavian
steal").
+ KEY FACTS
CLINICAL
• Most patients with retrograde flow in the vertebral
artery-i.e., angiographic subclavian steal-are asymptomatic.
Symptoms such as arm claudication (as in this
case) occur in only about one-third of patients with
angiographic findings of steal phenomenon. In a minority
of cases, ischemic vertebrobasilar symptoms ( e.g.,
clizziness, vertigo, and visual clisturbance) develop in
patients in whom these angiographic finclings are seen.
• The diagnosis is often suspected initially due to a discrepancy
in blood pressures between the arms.
• Data based on noninvasive studies such as sonography,
MRI, and MRA suggest that retrograde flow in the
381
vertebral artery may be more common than initially
thought.
RADIOLOGIC
• The typical angiographic finding in a patient with subclavian
steal is a high-grade stenosis (or occlusion) of
the subclavian artery proximal to the origin of the vertebral
artery. Retrograde flow in the vertebral artery
then provides blood supply to the distal segment of
the subclavian artery.
• The physiologic basis of neurologic symptoms due to
the subclavian steal phenomenon is as follows: Exerciserelated
increased blood demand in the arm supplied by
the affected subclavian artery causes hypoperfusion in
the territory of the vertebrobasilar circulation.
• Angiographic evaluation of patients with subclavian
steal should also include the carotid arteries, especially
in patients in whom the symptom complex is difficult
to localize to a vascular territory.
• Angioplasty has proved safe and effective in symptomatic
patients with subclavian steal syndrome. In many
centers, angioplasty has become the initial treatment of
choice. Ischemia or infarction in the vertebrobasilar
territory is a potential complication but is uncommon
because the contralateral vertebral artery and carotid
circulation almost always provide adequate collateral
supply.
+ SUGGESTED READING
Hebrang A, Maskovic J, Tomac B . Percutaneous transluminal angioplasty
of the subclavian arteries: Long-term results in 52 patients.
AJR Am J RoentgenoI 1 99 1 ; 1 56 : 1 09 1 -1094.
Hennerici M, Klemm C, Rautenberg W. The subclavian steal phenomenon:
A common vascular disorder with rare neurological
deficits. Neurology 1 988;38 :669-673.

Front 185

A 2-year-old asymptomatic girl with a cardiac murmur since birth.

Back 185

DIFFERENTIAL DIAGNOSIS
• Ventricular septal defect (VSD): VSDs produce
biventricular and left atrial enlargement and a normalsized
aorta. At cardiac catheterization, an extracardiac
shunt is not seen, w1like the cases shown above.
• Atrial septal defect (ASD): ASDs produce pure rightsided
cardiomegaly with a huge pulmonary trunk and
small aortic arch. At catheterization, the left-to-right
shunt is seen only at the atrial level, wilike the cases
shown here.
• Patent ductus arteriosus (PDA): Tlus lesion should
be considered because it produces cardiomegaly and
dilatation of the pulmonary arteries. A communication
between the aorta and pulmonary trunk is seen at aortography,
as in the cases shown above. This is the correct
diagnosis.
+ DIAGNOSIS: Left-to-right shunt via a patent
ductus arteriosus.
+ KBY FACTS
CLINICAL
• Patients with PDA are usually symptomatic in infancy
because of congestive heart failure. Older children and
adults with PDA tend to be asymptomatic until they
develop Eisenmenger's physiology.
• Because a left-to-right shunt is present, PDA patients
are not cyanotic. A continuous, "machinery-like" mur-
383
mur is usually heard over the left upper sternal border.
The electrocardiographic findings indicate left ventricular
and left atrial hypertrophy.
• Surgical ligation and division of the ductus is the standard
treatment. However, transcatheter occlusion of
the ductus is being increasingly performed with success.
RADIOLOGIC
• All pulmonary vessels are dilated as an expression of a
substantial left-to-right shunt.
• In the absence of congestive heart failure or
Eisenmenger's physiology, there is usually pure leftsided
cardiomegaly with dilatation of both great arteries.
• The passage of a catheter from the pulmonary trW1k to
the descending aorta alone is diagnostic of a PDA. The
lesion can be defined further by an aortogram showing
the point of commlullcation between the aorta and
pulmonary trunk. Furthermore, the aortogram can be
performed for therapeutic purposes-i. e . , embolization
of the PDA.
+ SUGGESTED READING
Chen JIT. Essentials of Cardiac Roentgenology. Boston : Little,
Brown, 1987.
Kelley MJ, Jaffe CC, Kleinman CS. Cardiac Imaging in Infants and
Children. Philadelphia: Sawlders, 1 982.
Nugent EW, Plaum WH, Edwards JE, Williams WH. The
Patllology, PatllOphysiology, Recognition, and Treatment of
Congenital Heart Disease. In RC Schlant, RW Alexander (cds),
The Heart ( 8tll cd). New York: McGraw-HilI, 1 994.

Front 186

A 34-year-old man who was told at the time of a military physical that he had an
"abnormal" chest radiograph

Back 186

DIFFERENTIAL DIAGNOSIS
• Aortic coarctation: In this entity, relative obstruction
of aortic flow leads to development of numerous collateral
vessels to the descending aorta. This fmding is
not present in the case shown above, making this diagnosis
unlikely.
• Pseudocoarctation of the aorta: This entity is characterized
by kinking of the aortic arch in the region of
the ligamentum arteriosus and elongation of the thoracic
aorta, but without formation of collateral vessels
because no obstruction to blood flow is present. This
diagnosis is most likely based on the imaging findings
shown in the case above. In the case shown, the shelflike
structure seen projecting from the aortic wall was
due to buckling of the aorta, not a true stenosis.
+ DIAGNOSIS: Pseudocoarctation of the thoracic
aorta.
KEY FACTS
CLINICAL
• Coarctation of the aorta is a common congenital
anomaly characterized by a discrete infolding of the
posterior wall of the descending thoracic aorta at the
level of the ligamentum arteriosus. In the postductal
or adult type, this defect is located just distal to the
insertion of the ductus arteriosus. Another form of
coarctation presents in infancy and is associated with
hypoplasia of the aortic arch. The posterior wall infolding
is located proximal to the ductus. The location of
the coarctation proximal to the ductus is thought to
prevent normal flow-stimulated development of the
aortic isthmus in utero.
385
• In both the pediatric and adult forms, aortic obstruction
leads to development of collateral vessels to the
descending aorta. In addition, coarctation may be
associated with a bicuspid aortic value ( 20% to 30%) or
a VSD .
• Pseudocoarctation o f the aorta i s also a congenital
anomaly consisting of buckling or kinking of the aortic
arch in the region of the ligamentum arteriosus.
Although embryologically and anatomically similar to
true aortic coarctation, no obstruction to blood flow is
present. In this condition, elongation of the thoracic
aorta is seen, but there are no collateral vessels coursing
to the descending aorta.
RADIOLOGIC
• Coronal and sagittal left anterior oblique T l -weighted
images as well as gradient echo images in similar imaging
planes can easily detect (and discriminate between)
coarctation and pseudocoarctation of the aorta.
Collateral vessels in the intercostal regions and
enlarged internal mammary arteries are present in true
aortic coarctation but not in pseudocoarctation.
+ SUGGESTED READING
Gomes AS, Lois JF, George B, et al. Congenital abnormalities of the
aortic arch: MR imaging. Radiology 1 987; 1 65 :69 1 -695 .
LePage JR, Szezchenyi E, Ross-Duggan JW. Pseudoarctation o f the
aorta. Magn Reson Imaging 1 988;6:65-68.
Shapiro IL, Bartolome M, Candiolo MD, et al. Pseudoarctation of
the aortic arch. Arch I ntern Med 1 968;122:345-348.

Front 187

A patient with dyspnea, deep venous thrombosis ( DVT), and a ventilationperfusion
scan indicating high probability for pulmonary embolism (PE). He is
referred for placement of an inferior vena cava (IVC) ftlter.

Back 187

DIFFERENTIAL DIAGNOSIS
The findings seen in Figure 7 - 19A indicate a retroaortic
left renal vein, a normal variant that occurs in 3% of the
population. This finding is important because this renal
vein is at the L4 level, instead of the usual L2 level.
Failure to note this fact before IVC filter placement could
result in inadvertent placement of a filter between the two
levels of the renal veins.
+DIAGNOSIS: Retroaortic left renal vein.
KEY FACTS
CLINICAL
• Indications for placement of an IVC filter for the prevention
of PE are:
a. Contraindication to anticoagulation in a patient
with either or both known DVT and PE.
b . Failure of anticoagulation with recurrent DVT or
PE, or a complication of anticoagulation.
c. Patients at high risk of substantial hemodynamic
compromise from even a small PE-e .g., a recent
PE with residual clot burden and limited pulmonary
reserve.
d. Prophylaxis in high-risk patients-e.g., before hip
replacement or in paraplegic patients. This is
done in some centers but is not widely accepted.
• Risks of IVC filter placement include:
a. Thrombosis at the insertion site (5% to 1 0%).
b. Injury to the vein used for access or the IVC
(which can be lethal) .
c . Filter migration, a rare event i f the IVC i s measured
before placement and the device properly
deployed. Long-term migration is not infrequent
but usually is caudal to the original placement site.
d. Filter fracture, a rare event that can occur after
prolonged use, potentially penetrating the IVC or
adjacent organs.
e. PE recurrence despite appropriate fliter placement
( 3% to 5%).
f. IVC occlusion. This occurs in 1 0% to 20% of
cases and is usually asymptomatic, but it can
cause marked leg edema.
• There are currently six Food and Drug Administrationapproved
types of filters available.
a. The first three types are varieties of the Greenfield
filter ( Medi-Tech ) : one titanium and two
387
stainless steel versions. The original version is seldom
used due to tlle large sheath required. A
new version is deployed over a wire.
The remaining types include:
b. Simon-Nitinol ( Nitinol Medical Technologies,
Inc) : The small size and malleable nature make
this device tlle only filter that can be deployed
from a peripheral vein.
c . Gianturco-Roehm Bird's Nest ( Cook, Inc . ) : This
filter is the only device that can be deployed in an
IVC measuring >28 mm. The maximal IVC
diameter in which it can be used is 40 mm.
d. Vena-Tech ( Braun) .
RADIOLOGIC
• Cavography is performed to determine patency of the
IVC and iliac veins, IVC size, and position of the renal
veins. The presence of thrombus in the iliac vein is an
indication to use an entry site through the contralateral
iliac vein or the right j ugular vein.
• An IVC measuring >28 mm is an indication to place
filters within each common iliac vein or a bird's nest
filter in tlle IVC.
• The top of the fliter should be placed about 1 cm
below the lowest renal vein. In the case shown above,
placement of a filter at a point between the levels of
the renal veins could cause left renal vein thrombosis.
• All brands of filters can be inserted via either a femoral
or jugular vein entry, but individual filters are specifically
designed for only one of tllese approaches (except
the bird's nest filter).
• Manipulation of a tilted or migrated filter should rarely
be performed, and then only by an experienced operator.
The treatment when a fliter has migrated or
severely tilted is placement of a second filter above tlle
first, usually from a jugular approach.

Front 188

A 7 -day-old child with tachypnea, cyanosis, bilateral crackling rales, and a heart
murmur. Her cyanosis deepened during feeding.

Back 188

DIFFERENTIAL DIAGNOSIS
• Hypoplastic left heart syndrome: This entity is a
cause of neonatal cyanotic heart disease and severe pulmonary
edema. There are severe left-sided obstructive
lesions with a right-to-left shunt at the ductal level and
a left-to-right shunt at the atrial level. There may be
differential cyanosis with pink arms and blue legs.
Three facts make this diagnosis unlikely: ( 1 ) the cardiac
size is usually markedly enlarged, ( 2 ) the pulmonary
veins drain normally into the left atrium, and
( 3 ) differential cyanosis is often present. None of these
features is present in the case shown .
• Left-sided obstructive lesions: These lesions-e .g.,
aortic stenosis and coarctation of the aorta-may present
in the neonatal period with severe congestive
heart failure. However, two facts make this diagnosis
unlikely: ( 1 ) patients with these lesions are not cyanotic,
and ( 2 ) the heart is usually markedly enlarged.
• Systemic arteriovenous (AV) fistulae: These
lesions-e.g., huge AV fistulae involving the vein of
Galen or the liver-can cause frank congestive heart
failure early in life . However, this diagnosis is unlikely
for three reasons: ( 1 ) patients with these lesions are
not cyanotic, ( 2 ) the heart is markedly enlarged, and
( 3 ) the pulmonary vessels are significantly dilated due
to increased blood flow.
• Total anomalous pulmonary venous return: In this
entity, patients are cyanotic (worsening during feeding,
as in tlle case illustrated), have pulmonary edema, and
have a normal heart size. These features, along Witll
the pulmonary angiogram findings shown above, make
this the correct diagnosis.
+ DIAGNOSIS: Total anomalous pulmonary venous
connection to the portal vein with obstruction.
KEY FACTS
CLINICAL
• Neonates with severe congestive heart failure due to
this disorder present with cyanosis, tachypnea, and
389
crackling rales. Frequently the rales are loud enough to
obscure the cardiac murmur. Because the heart size is
normal, newborn respiratory distress syndrome can be
mistakenly diagnosed.
• Helpful clues to me correct diagnosis include ( 1 ) normal
heart size, ( 2 ) severe pulmonary edema, and ( 3 ) deepening
cyanosis wim feeding.
• Without surgical intervention, patients progressively
worsen.
• Emergency surgical repair is indicated and consists of
anastomosis of me pulmonary venous confluence
( almost always found just behind the left atrium ) to
me left atrium. Thereafter, me atrial septal defect is
repaired.
RADIOLOGIC
• In this disease process, me common collecting pulmonary
vein is severely obstructed by born intrinsic
stenoses and extrinsic compression at multiple sitese.
g., during passage tl1rough the esophageal hiatus and
at me level of me capillary bed of me liver.
• Immediate definitive diagnosis is indicated in this disease
process if a good outcome is to be reached. The radiologist
can play a major role by initially suggesting me
diagnosis and men confirming it by imaging studies.
• The diagnosis can be made by a number of means, including
echocardiography, MRI, and angiocardiography.
+ SUGGESTED READING
Burrows PE, SmalJhorn JF, Moes CAF. Congenital Cardiovascular
Disease. In CE Putman, CE Ravin (cds), Textbook of Diagnostic
Imaging (2nd ed). Philadelphia: Saunders, 1994.
Chen JTT. Essentials of Cardiac Roentgenology. Boston: Little,
Brown, 1987.
Kelley MJ, Jaffee CC, Kleinman CS. Cardiac Imaging in Infants and
Children. Philadelphia: Saunders, 1 982.
Nugent EW, Plautll WH, Edwards JE, Williams WH. The
Patllology, Patl1ophysiology, Recognition, and Treatment of
Congenital Heart Disease. In RC Schlant, RW Alexander (eds),
The Heart (8tll ed ) . New York: McGraw- Hill, 1994.

Front 189

A l O-month-old girl with worsening cyanosis smce 3 months of age.

Back 189

DIFFERENTIAL DIAGNOSIS
• Pseudotruncus arteriosus: This entity is the most
severe form of tetralogy and is impossible to distinguish
from tetralogy of Fallot (TOF) on chest radiographs.
It has a higher incidence of right-sided aortic
arch than TOF. The ventriculograms help to distinguish
the two entities because pulmonary atresia
(rather than the infundibular pulmonary stenosis
shown above ) is present in pseudotruncus arteriosus.
• Ebstein's anomaly: Ebstein's anomaly might be
considered because it presents clinically with cyanosis
and has the radiographic finding of decreased pulmonary
vascularity. However, the cardiac size is
much larger in Ebstein's anomaly than in the cases
shown because of considerable volume overload
caused by tricuspid insufficiency without a ventricular
septal defect (VS D ) .
• Pulmonary atresia without a VSD: As i n the case of
Ebstein's anomaly, the heart tends to be much bigger
in patients with this disease than in the cases shown
above because a VSD is not present.
• Tricuspid atresia: Flattening of the right atrial border
on the posteroanterior view and that of the right ventricular
border on the lateral view is usually seen in tricuspid
atresia. These findings are not present in the
cases shown above.
• TOF: The boot-shaped cardiac contour, upward tilt of
the heart, and pulmonary concavity are typical ofTOF.
The VSD and overriding aorta shown on the ventriculogram
are characteristic findings.
DIAGNOSIS: Severe tetralogy of Fallot with a
right-sided aortic arch.
KEY FACTS
CLINICAL
391
• Patients with severe TOF usually become symptomatic
after 3 or 4 months of life .
• These patients are cyanotic and have a high hematocrit.
They characteristically need to squat to decrease
their dyspnea. Clubbing of the fingers is typically seen.
RADIOLOGIC
• All pulmonary vessels are small, with hyperlucent
lungs. A decrease in pulmonary vascularity is seen routinely,
primarily due to a large right-to-Ieft shunt
across the VSD.
• The odd shape of the heart is likened to a wooden shoe
( coeur en sabot is the original description in French).
• Angiocardiography shows ( 1 ) severe infundibular pulmonary
stenosis ( PS); ( 2 ) mild valvular PS; ( 3 ) large
VSD shunting blood right-to-Ieft; (4) hypertrophy of
the right ventricle; and ( 5 ) an overriding of the aorta,
which is dilated. Right-sided aortic arch occurs in 25%
to 50% of cases in proportion to the degree of PS.
• SUGGESTED READING
Chen JIT. Essentials of Cardiac Roentgenology. Boston: Little,
Brown, 1987.
KeUey MJ, Jaffe CC, Kleinman CS. Cardiac Imaging in Infants and
Children. Philadelphia: Saunders, 1 982.
Nugent EW, Plauth WH, Edwards JE, Williams WH. The
Pathology, Pathophysiology, Recognition, and Treatment of
Congenital Heart Disease. I n RC ScWant, RW Alexander (eds),
The Heart (8th ed). ew York: McGraw-Hill, 1994

Front 190

An I S-year-old male basketball player with chest pain

Back 190

DIFFERENTIAL DIAGNOSIS
Many common conditions can cause a dilated ascending
aorta, including lesions that cause turbulence (e.g., aortic
stenosis), volume overload ( e .g., aortic regurgitation), or
pressure overload (e.g., hypertension ) . However, the finding
of an intimal flap within the ascending aorta is direct
evidence of aortic dissection as the cause of the aortic
dilatation in the case shown above.
+ DIAGNOSES: Dissection of the ascending thoracic
aorta (DeBakey type II, Stanford type A), and probable
annuloaortic ectasia (see Case 1 5 in this chapter).
+ KEY FACTS
CLINICAL
• Dissection of the thoracic aortic wall is the result of
repeated trauma to the arterial media. The most frequent
etiology is hypertension. The formation of a
hematoma in the media and subsequently the serosa
results in loss of support of the intima. A tear can then
form in the intima with the false lumen propagating
along the media.
• Dissections commonly develop in aortas that have
underlying abnormalities of the media, such as cystic
medial necrosis, Marfan's syndrome, and annuloaortic
ectasia.
• Dissections involving the descending aorta respond
well to control of underlying hypertension. Involvement
of the ascending aorta constitutes a surgical
emergency.
• The following classifications are those used to refer to
forms of aortic dissection:
a. DeBakey Type I: dissection involves the ascending
aorta, transverse arch, and descending aorta
b. DeBakey Type I I : dissection confmed to the
ascending aorta
c. DeBakey Type III: dissection confined to the
descending aorta, distal to the left subclavian artery
d. Stanford Type A: dissection involves the ascending
aorta ( DeBakey I and I I )
393
e. Stanford Type B: dissection confined to descending
aorta ( DeBakey III)
• The ascending aorta ( as in the case shown above) is
involved in approximately 60% of dissections, and the
descending aorta in 40%.
RADIOLOGIC
• In hemodynamically stable patients with suspected or
known thoracic aortic disease, such as aortic dissection,
MRI is the imaging study of choice. MRI allows the
location and extent of the dissection (including
involvement of the ascending aorta, descending aorta,
or both) to be shown in a noninvasive manner.
• Direct and indirect signs of aortic dissection on MRI
are similar to those seen with other imaging techniques.
The pathognomonic direct findings are the
presence of an intimal flap and a double lumen.
Indirect findings include compression of the true
lumen, thickening of the aortic wall, aortic regurgitation,
and ulceration projecting beyond the aortic wall.
• Dynamic techniques such as gradient echo MRI must
be used to assess the aortic valve and exclude pericardial
effusion. Slow flow in the false lumen can be difficult
to distinguish from partial thrombosis of the false
lumen. Phase mapping techniques have been suggested
as a way to resolve tl1is question.
+ SUGGESTED READING
Kersting-Sommerhoff BA, Higgins CB, White RD, et al. Aortic dissection:
Sensitivity and specificity of MR imaging. Radiology
1988 ; 1 66:65 1-655.
Link KM, Lesko NM. The role of M R imaging in the evaluation of
acquired diseases of dle dlOracic aorta. AJR Am J Roentgenol
1992 ; 1 58 : 1 1 1 5- 1 1 2 5 .
Nienaber CA, von Kodolitsch Y , Nicolas V, e t al. The diagnosis of
thoracic aortic dissection by noninvasive imaging procedures. N
Engl J Med 1 993;328: 1-9.
Nugent EW, Plaudl WH, Edwards JE, Williams WH. The
Pathology, Pathophysiology, Recognition, and Treatment of
Congenital Heart Disease. In RC Schlant, RW Alexander (eds),
The Heart (8dl ed). New York: McGraw-Hill, 1994.

Front 191

A 46-year-old man with a history of cigarette smoking and coronary artery disease.
He has a 2-year history of postprandial abdominal pain.

Back 191

Atherosclerotic disease: This entity is the most common
cause of proximal occlusion of the mesenteric
arteries and can cause chronic mesenteric ischemia if
two of the three major arteries supplying the bowel are
occluded.
• Abdominal aortic aneurysm: Mural thrombus in an
abdominal aortic aneurysm can narrow the origin of
mesenteric arteries or embolize into the vessels, causing
an acute mesenteric ischemia. However, the external
diameter of the aorta would be expected to be enlarged
with a filling defect within an aneurysm. These findings
are not seen in the case presented above.
• Aortic dissection: The false channel of an aortic dissection
can involve the mesenteric artery origins and
cause acute mesenteric ischemia (see Case 1 5 ) .
However, in the presence of aortic dissection, two
contrast-filled chatmels or a narrowed true lUI1len adjacent
to a thrombosed false lumen would be expected.
Those findings are not present in the case illustrated.
• Embolic occlusion: Emboli related to cardiac arrhythmias
or myocardial infarction can travel to the mesenteric
arteries, resulting in acute mesenteric ischemia.
The clinical history of chronic symptoms is not compatible
with this diagnosis. Furthermore, the expected
findings of multiple branch occlusions or intraluminal
filling defects are not present in the case shown above.
DIAGNOSIS: Chronic mesenteric ischemia due
to atherosclerotic disease.
KEY FACTS
CLINICAL
• Atherosclerotic occlusion of the vessel origins occurs
slowly, usually allowing formation of adequate coIl ateral
arterial supply for bowel viability.
• The pancreaticoduodenal arteries are the major source
of coIlateral circulation between the celiac artery at1d
superior mesenteric artery (SMA).
• The marginal artery of Drummond and the arc of
Riolan provide collateral circulation between the SMA
and the inferior mesenteric artery ( IMA) .
395
• The IMA receives collateral supply from the middle
and inferior hemorrhoidal arteries, which arise from
the internal iliac arteries.
• When two or more of the major mesenteric arteries
become occluded near their origin, even the collateral
blood supply is affected, and mesenteric ischemia can
result.
• Symptoms of abdominal pain due to mesenteric
ischemia are often ill-defil1ed and Cat1 mimic other disease
states-e .g., gastrointestinal malignancy and peptic
ulcer disease. The most common complaints are
those of weight loss, diarrhea, and abdominal pain.
Postprat1dial pain (usually within 2 hours of eating) is
common and can cause the patient to avoiding eating.
• Treatment typically consists of surgical bypass.
Percutaneous balloon angioplasty has a high technical
success rate but has been shown to be less effective
that1 surgery for long-term symptomatic relief.
RADIOLOGIC
• Abdominal aortography is essential for evaluating the
proximal segments of the celiac, superior mesenteric,
and inferior mesenteric arteries.
• The diagnosis of chronic mesenteric ischemia is confirmed
by the angiographic finding of severe stenosis or
occlusion of at least two of the major mesenteric arteries.
• If the proximal segments of the artery are seen to be
normal at angiography, selective catheterization is necessary
to rule out a mesenteric steal phenomenon
caused by a mesenteric arteriovenous fistula or arterialto-
arterial shunts that can be seen when the lower
aorta is occluded. Peripheral branch stenoses or occlusions
are rarely responsible for ischemia.

Front 192

A 14-year-old acyanotic girl with Down's syndrome.

Back 192

DIFFERENTIAL DIAGNOSIS
• Atrial septal defects (ASDs) are commonly classified
into three types: sinus venosus, ostium secundum, and
ostium primum. The ostium secundum defect is the
most common form and occurs in the midseptal
region at the fossa ovalis. TIllS entity is the most common
type of congenital heart clisease in adults. Sinus
venosus defects are often associated with anomalous
return of the right upper lobe pulmonary vein into the
superior vena cava (SVC) or right atrium.
DIAGNOSES: Ostium primum atrial septal
defect and persistent left superior vena cava.
KEY FACTS
CLINICAL
• The ostium primum ASD is part of the spectrum of
arteriovenous (AV) septal defects. It occurs in the central
AV region near the confluence of the lower atrium
septum, the AV valves, and the membranous ventricular
septum. Ostium primum ASD is invariably associated
with a cleft in the anterior leaflet of the mitral
valve . The defect may be partial (as in tllls case ) , intermecliate,
or complete. A complete defect is associated
with a common AV valve and a moderate-to-Iarge
VSD. Approximately 40% of children with a complete
AV canal have Down's syndrome.
• One or more pulmonary veins may connect to the
right atrium or its inflow connections (SVC, inferior
vena cava, coronary sinus, innominate vein, etc . ) . The
397
most common supracarcliac anomaly is anomalous
venous cOImection of the upper lobe pulmonary vein
to tl1e left innonlinate vein via the left vertical vein. A
persistent left SVC occurs witl1 a prevalence of 0.5%
and usually drains into the coronary sinus. When it
drains into the left atrium ( as in the case shown
above ) , the coronary sinus is absent.
RADIOLOGIC
• Findings of endocarclial cusillon defects on MRI
include moderate enlargement of the right atrium and
right ventricle, but usually the left atrium is normal in
size wlless severe mitral regurgitation is also present.
• On MRI, the ASD can be seen at the level of the AV
valves.
• Mitral regurgitation can be detected readily on graclient
echo MRI. Right ventricular free wail hypertrophy
( > 1 cm) can be seen in the presence of associated pulmonary
hypertension.
• SUGGESTED READING
Dinsmore RE, Wismer GL, Guyer D, et al. Magnetic resonance
imaging of the intra-atrial septum and atrial septal defects. AJR
Am J Roentgenol 1 985; 145 :697-703 .
Higgins CB. MRl of Congenital Heart Disease. In CB Higgins (ed),
Essentials of Cardiac Radiology and Imaging. Philadelphia:
Lippincott, 1 992.
Lowell DG, Turner DA, Smith SM, et al. The detection of atrial and
ventricular septal defects with electrocardiographically synchronized
magnetic resonance imaging. Circulation 1 986;73:89-94.
Perloff JK. Congenital heart disease in adults: A new cardiovascular
subspecialty. Circulation 1 99 1 ;84: 1 8 8 1-1 890.

Front 193

A middle-aged man previously had undergone percutaneous nephrostomy (PCN)
for treatment of renal obstruction due to stricture of a ureteroileal loop anastosmosis.
A catheter exchange was attempted to introduce a larger catheter for stricture
dilatation. At a point when only a guidewire (and no catheter) was in place, brisk
pulsatile bleeding from the PCN tract was seen.

Back 193

Brisk bleeding from a PCN site almost invariably is
due to arterial injury. The injury can be an arterial tear
(which can be accompanied by pseudoaneurysm formation)
or arterial transection. If no arterial injury is
seen at angiography, considerations include hemorrhage
due to an arterial injury that has ceased bleeding,
a bleeding diathesis, inadvertent catheter
placement through a vascular abnormality such as a
tumor, or, less likely, renal vein injury.
+ DIAGNOSIS: Hemorrhage due to arterial injury.
+ KEY FACTS
CLINICAL
• Indications for PCN include ( 1 ) renal or ureteral
obstruction, ( 2 ) need for access for an interventional
procedure (e.g., stone extraction or lithotripsy, stricture
dilatation, or to aid retrograde access) , ( 3 ) renal abscess
drainage or direct antibiotic infusion into a site of fungal
infection, and (4) urinary diversion (e.g., during
treatment of ureteral injuries or hemorrhagic cystitis).
• Mild hematuria is seen frequently after placement and is
not considered a serious complication. The rate of major
complication during PCN placement is dO%.
Complications of PCN and nephroureteral catheter
placement can include: ( 1 ) sepsis, which is the most
common complication (seen in 1% to 9% of cases);
(2) frank hemorrhage, which can be either acute or
delayed in onset; ( 3 ) perforation of the renal collecting
system (e.g., ureteral injury) ; (4) inadvertent injury of
adjacent organs ( usually colon or spleen); or ( 5 ) pneumothorax,
when the route of entry is not subcostal.
• Bleeding can result from ( 1 ) renal parenchymal or capsular
injury, (2) arterial injury causing transection (as in the case
shown), laceration, or formation of a pseudoaneurysm or
arteriovenous fistula. Arterial injury typically involves tl1e
renal artery, but nonrenal arteries (e.g., tl1e intercostal
artery) can also be injured and cause frank hemorrhage.
• Proper preprocedure patient management includes
( 1 ) assessment of findings from other in1aging studies
indicating the rationale for the procedure, ( 2 ) recording
of pertinent recent laboratory studies ( e .g., hematocrit,
hemoglobin, platelet count, coagulation studies,
and renal function studies) , ( 3 ) establishment of a
secure intravenous line, (4) provision of adequate analgesia,
and ( 5 ) administration of broad -spectrum anti biotics
for prophylaxis against gram-negative organisms.
RADIOLOGIC
• Either sonography or fluoroscopy is used as guidance
for access. If fluoroscopy is used and renal function is
normal, the renal collecting system is typically opacified
using intravenous contrast administration. Alternatively,
a "blind" approach may be taken using anatomic landmarks.
Small-gauge needles (20 or 22 g) are usually
used for initial access.
399
• Usually an attempt is made to place the needle in a
posterior lower pole calyx because there is a relative
paucity of arteries in this region ( "Brodal's bloodless
incision line " ) compared to the more vascular upper
pole. Entry into an upper pole calyx could have contributed
to tl1e hemorrhagic complication in the
patient shown above. The calyx should be entered
end-on to avoid injury to the arcuate arteries traversing
tl1e infundibular portion of the calyx. An anterior
calyx entry point should be avoided because it makes
passage of wires and catheters difficult.
• The choice of catl1eters for drainage procedures varies,
but generally an 8 or 1 0 F, self-retaining, pigtail catheter
is used, with the pigtail tip left within the renal pelvis.
• When the renal collecting system is infected, caution
must be exercised to minimize the amount of air or
contrast material used to distend the collecting system
so that the risk of sepsis is minimized. If sepsis develops,
urine in the renal pelvis is aspirated, catheter placement
is completed as quickly as possible, and as necessary,
fluid resuscitation and antibiotic administration are
started. If the collecting system is infected, any additiona
procedures are usually deferred until a later time.
• Brisk, pulsatile, or nonremitting bleeding from the
catheter, tract, or bladder should raise suspicion of vascular
injury. The first step in treatment should be tamponade
of the bleeding site by the catheter, which may
require placement of a larger catl1eter.

Front 194

A l O-year-old girl with a history of cyanosis, squatting, and clubbing of fmgers
since early childhood.

Back 194

DIFFERENTIAL DIAGNOSIS
• Isolated pulmonary atresia with competent tricuspid
valve: This is an unlikely diagnosis in a patient of this
age because patients usually succumb shortly after birth.
• Isolated pulmonary atresia with incompetent tricuspid
valve: This diagnosis might be considered
based on the angiogram findings of atresia of the pulmonary
outflow tract seen in Figure 7-26B. However,
this diagnosis is incorrect for two reasons: first, a ventricular
septal defect (VSD) is present in the case
shown above, but would not be expected in isolated
pulmonary atresia; and second, right ventricle hypertrophy
( but not dilatation) is present in the case shown
above, whereas marked dilatation of the right ventricle
would be expected in isolated pulmonary atresia.
• Admixture lesions with pulmonary stenosis:
Examples of this category include ( 1 ) D-loop transposition
of the great arteries with pulmonic stenosis, and
( 2 ) double-outlet right ventricle with pulmonic stenosis.
These lesions could mimic the present case. It
would be difficult to distinguish them on the basis of
clinical grounds or plain radiographs, but the echocardiography
and cardiac catheterization findings would
differ from those in the case illustrated.
• Pulmonary atresia with VSD: This is the best diagnosis
given tlle clinical presentation and the radiologic
findings of coexistent atresia of the pulmonary outflow
tract, a VSD, and right ventricle hypertrophy.
+DIAGNOSIS: Pulmonary atresia with ventricular
septal defect (severe tetralogy of Fallot).
+ KEY FACTS
CLINICAL
• The physiology of pulmonary atresia with VSD is
essentially that of severe TOP.
• Without surgery, 75% of these patients die within 1 0
years. Cyanotic spells indicate severe pulmonary steno-
401
sis. Complete obstruction can ensue with poor surgical
outcome.
• The method of surgical repair depends on whetller the
branch pulmonary arteries are confluent. Confluent
pulmonary arteries can be repaired with a conduit.
Nonconfluent arteries may require a palliative shunt or
unifocalization (i.e., creation of a common conduct
encompassing all the separate pulmonary arteries from
both lungs ) .
• Numerous small and tortuous vessels i n both upper
lung zones are frequently seen, representing bronchial
arterial collateral circulation.
RADIOLOGIC
• The initial chest radiographic findings of pulmonary
atresia Witll VSD are the same as those for severe TOP.
• The coeur en sabot ( "boot-shaped" ) cardiovascular configuration
is explained by the enlarged right ventricle,
which displaces the left ventricle leftward, posteriorly,
and superiorly and causes uptilting of the cardiac apex.
• Both infundibular pulmonic stenosis and hypoplasia of
pulmonary arteries can also cause a concavity in the
region of tile pulmonary trunk.
• The large right-to-left shunt via a VSD is responsible
for a markedly dilated aorta.
• Severe pulmonary oligemia is caused by the large
right-to-left shunt.
+ SUGGESTED READING
Chen JTI. Essentials of Cardiac Roentgenology. Boston: Little,
Brown, 1 987.
Kelley MJ, Jaffe CC, Kleinman CS. Cardiac Imaging in Infants and
Children. Philade1phja: Saunders, 1982.
Nugent EW, Plautl1 WH, Edwards JE, Williams WH. The
Pamology, PatllOphysiology, Recognjtion, and Treatment of
Congenital Heart Disease. In RC Schlant, RW Alexander (eds),
The Heart (8tl1 cd). New York: McGraw-Hill, 1 994

Front 195

A left-handed baseball pitcher with pain and numbness in the left hand and forearm
when throwing a ball.

Back 195

DIFFERENTIAL DIAGNOSIS
• Thoracic outlet syndrome: The findings on the second
angiogram, if viewed in isolation, could be due to
a wide number of entities. However, when the findings
of the two angiograms are considered together, the
occlusion of the subclavian artery must be explained by
arterial compression due to change in the position of
the arm. Such compression would most likely be due
to arterial compression by adjacent muscle or rib.
+ DIAGNOSIS: Thoracic outlet syndrome.
+ KEY FACTS
CLINICAL
• The axillary artery is the continuation of the subclavian
artery and is defined as the segment extending from
the lateral margin of the first rib to the inferior lateral
margin of the teres major muscle. Distal to this point,
the artery continues as the brachial artery.
• Thoracic outlet syndrome results from compression of
the nerves and vessels as they course through the upper
thorax and shoulder in the region referred to as the
"thoracic outlet." These structures can be compressed at
several sites (most commonly the interscalene triangle,
costoclavicular space, and the pectoralis minor triangle)
and by a number of mechanisms, including compression
by a rib or fibrous bands. The distal location of the
occlusion in the case shown suggests that compression
by the pectoralis minor muscle (which became hypertrophied
secondary to the repeated arm motions involved
in pitching) is the most likely etiology.
• More commonly, the subclavian artery is compressed
by the first rib or an anomalous cervical rib. The diagnosis
is often first suspected based on clinical history
and physical findings of diminished pulses or reproducible
pain on abduction of the arm.
403
• Thrombosis at the site of arterial compression or distal
embolization can rarely cause limb ischemia.
RADIOLOGIC
• On occasion, chest radiographs may show a cervical rib
as a suspected cause of vascular compromise.
• Doppler sonography can serve as a helpful noninvasive
study for detection of arterial compression.
• Selective angiography of the subclavian artery is indicated
when ischemia is a prominent feature and
surgery is a consideration. The artery is injected iilltially
with the arm in neutral (adducted) position. The
entire arterial supply of the arm should be evaluated
for evidence of distal embolization. Thereafter, the arm
is hyperabducted and repeat filming performed over
the shoulder region.
• Angiographic findings in thoracic outlet syndrome
include subclavian or axillary artery stenosis or occlusion
(occasionally in neutral position rather than during
abduction), poststenotic dilatation, arterial
displacement, pseudoaneurysm, thrombosis, and distal
embolization.
• Patients whose symptoms are severe enough to warrant
angiographic evaluation are often surgical candidates.
The most common surgical approaches include resection
of the first rib or a cervical rib, if present, and
release of fascial bands surrounding nerves and vessels.
+ SUGGESTED READING
Fechter JD, Kuschner SH. The thoracic outlet syndrome. Rev
Ortllop 1 99 3; 1 6 : 1 243- 1 2 5 l .
Kamr S. Diagnostic Angiography. Philadelphia: Saunders, 1986.
Kutz JE, Rowland EB Jr. Vascular compression about tlle shoulder.
Hand elin 1993;9 : 1 3 1 - 1 3 8 .

Front 196

A newborn boy noted to be extremely cyanotic, tachypneic, and tachycardic. An
emergency palliative procedure has been performed

Back 196

Large ventricular septal defect (VSD): Patients with
a large VSD can become dusky when in severe congestive
heart failure, but they are not cyanotic. Furthermore,
the patients presented here were not in congestive
heart failure. Newborns with a VSD do not have
increased pulmonary blood flow due to physiologic
high pulmonary vascular resistance. Shunting is
insignificant until pulmonary resistance falls, but thereafter
proceeds in a Ieft-to-right direction. These factors
all argue against the diagnosis of a large VSD as the
diagnosis in the cases shown.
• Hypoplastic left heart syndrome: Patients with this
syndrome are also cyanotic neonates, but they are
almost always in profound heart failure with pulmonary
edema ( and do not have increased pulmonary
flow, as in the case presented) . Furthermore, their
hearts tend to be larger than those seen in the cases
shown. These factors make this diagnosis unlikely.
• Total anomalous pulmonary venous connection with
obstruction: These patients are also cyanotic neonates,
but they are always in profound heart failure with severe
pulmonary edema and have a normal cardiac size.
• Atrial septal defect (ASD): This defect can have a
variety of clinical presentations, depending on the size
and location of the defect. It usually presents late in
infancy ( unlike the case presented here ), with pulmonary
overcirculation following a fall in the pulmonary
vascular resistance. Furthermore, patients with
this disorder do not have a narrow superior mediastinum,
because the great vessels are normally related.
Finally, patients with ASD are not cyanotic. This is an
incorrect diagnosis.
• D-Ioop transposition of the great arteries: This
diagnosis is the best choice, given the history and radiographic
findings. The characteristic findings are present
on the angiogram, confirming the diagnosis.
DIAGNOSIS: D-Ioop transposition of great
arteries (TOGA), patent ductus arteriosus status
post-atrial septostomy.
+ KEY FACTS
CLINICAL
• D-Ioop transposition of great arteries accounts for 4%
of congenital cardiac defects in children.
• D-Ioop transposition of great arteries is the most common
lesion to present with severe cyanosis immediately
after birth.
405
• Infants with an intact ventricular septum are usually
severely cyanotic but not in congestive heart failure.
The patency of either or both the ductus and the foramen
ovale allows for initial survival, but atrial septostomy
is required for long-term survival.
• The diagnosis is usually established by echocardiography,
which may be sufficient for operative planning; a
septostomy may be performed using angiographic or
sonographic guidance.
• Current definitive repair is the Jatene procedure, in
which the aorta and pulmonary vessels are switched.
Previously, Mustard and Senning atrial baffle procedures
were performed. These procedures resulted in a
systernic right ventricle that eventually failed.
RADIOLOGIC
• Following emergency atrial septostomy, there is increased
pulmonary vascularity with moderate cardiomegaly.
• The "egg on the string" appearance of the heart is due
to several factors. The right heart is pumping against
the high systernic vascular resistance and is enlarged to
a greater degree than the left heart. Hence, a globular
cardiac contour results. The thymus is absent due to
the stress, and the aorta and main pulmonary artery
take on a more overlapping configuration.
• For D-Ioop TOGA, the angiocardiographic findings
are usually also well shown by echocardiography. The
basic pathologic anatomy is as follows: The aorta arises
from the right ventricle and the pulmonary artery
arises from the left ventricle. The parallel arrangement
of the two circulations is incompatible with life without
some kind of communication (either patent foramen
ovale, ASDjVSD, or a septostomy) .
• The pathophysiology of this entity can b e considered
as a spectrum with two extremes. On one end, communications
between the right and left circulatory
pathways are too numerous and too large, resulting in
pulmonary plethora, congestive heart failure, and mild
cyanosis. On the other end, communications are too
small and too few in number, causing pulmonary
oligemia and severe cyanosis but not heart failure.

Front 197

A 24-year-old man with a long history of respiratory difficulty, frequent pulmonary
infections, and recent onset of hemoptysis.

Back 197

A wide range of entities can produce the radiographic
appearance seen in Figure 7-29A. These entities include:
• Cystic fibrosis: This is the most likely diagnosis in a
young patient with the findings shown in Figure
7 -29A, especially given the associated finding of
dilated bronchial arteries seen in Figure 7-29B.
• Collagen disorders: The findings shown above can be
seen in some collagen vascular disorders, especially
ankylosing spondylitis. However, the presence of
bronchiectasis and the absence of skeletal abnormalities
are evidence against this diagnosis.
• Tuberculosis (TB) and atypical mycobacterial infections:
TB and atypical mycobacterial infections, such
as Mycobacterium avium complex, could produce the
changes shown in Figure 7-29A ( see below) .
• Sarcoidosis: The above findings can be seen in sarcoidosis.
However, low lung volumes, rather than the
increased lung volumes shown above, would be
expected.
• Pneumoconiosis: The absence of nodularity and conglomerate
masses makes this diagnosis less likely.
• Hemoptysis with enlarged bronchial arteries can be
produced by many causes, such as TB, coal worker's
pneumoconiosis, bronchiectasis, aspergillosis, carcinoma,
and congenital heart disease ( due to enlarged
collateral vessels) . However, the young age of the
patient in the case shown above, the lack of a history
of appropriate exposure to TB, coal dust, etc . , and the
radiologic findings shown in Figure 7-29A are most
consistent with cystic fibrosis.
+ DIAGNOSIS: Cystic fibrosis with enlarged
bronchial arteries.
+ KEY FACTS
CLINICAL
• If untreated, severe hemoptysis of any cause has a 50%
to 85% mortality rate (although it is probably less in the
cystic fibrosis population). Asphyxiation and, less commonly,
exsanguination are the major causes of death .
• The bronchial arteries usually arise between the T3
and T8 levels, but the sites of origin vary considerably
among individuals. Variations in the number of
bronchial arteries are also frequently seen, but the
common patterns are: ( 1 ) two left arteries and one
right artery (40%), ( 2 ) a single right and single left
bronchial artery ( 30%), and ( 3 ) two left and two right
arteries (20%). The bronchial arteries may share a common
origin with the intercostal arteries (so-called
"intercostobronchial trunk" ) .
• Systemic arterial supply t o the lungs i s actually from
two sources: bronchial arteries and non bronchial arteries.
The latter source includes branches of the subclavian
artery and proximal axillary arteries, including the
internal mammary, intercostal, and phrenic arteries.
Supply from these sites is common in patients with
cystic fibrosis. Theses sites should all be evaluated in
the cystic fibrosis patient with hemoptysis.
RADIOLOGIC
• Careful angiographic evaluation must be performed
before embolization to determine arterial feeding sites
of hemoptysis and define anatomic variants. In particular,
the angiographer must define the arterial supply to
the spinal cord and exclude the presence of large fistulous
connections to the pulmonary artery ( to protect
against inadvertent embolization of the spinal cord and
uninvolved segments of lung, respectively) .
• Generally, only angiography o f the bronchial arteries is
performed during evaluation of hemoptysis. Angiography
of the pulmonary arteries is reserved for cases in
which parenchymal necrosis is suspected.
• Bronchial arteries and non bronchial systemic arteries
that are responsible for hemorrhage are usually quite
enlarged.
• The site of hemoptysis is often only generalized to one
lung or the other by bronchoscopy, or may be unknown
even after angiography. Contrast material extravasation,
even in patients with hemoptysis, is very rare. Therefore,
embolization is performed whenever technically possible

Front 198

A 22-year-old man who sustained a gunshot wound to the left arm and is found to
have decreased left arm pulses.

Back 198

Vasospasm: Vasospasm can occur after trauma.
However, this diagnosis would not account for all of
the findings in the brachial artery (e.g., the linear
lucency and the extraluminal contrast collections),
making this diagnosis by itself incorrect.
• Arterial dissection: The linear lucency extending
along the brachial artery is, in fact, due to arterial dissection.
However, this diagnosis alone does not
account for all of the findings, including the extraluminal
collections and the findings in the digits.
• Arterial injury with distal thromboembolization:
This is the correct diagnosis. The extraluminal contrast
collections are due to small sites of arterial hemorrhage.
The numerous ftiling defects in digital arteries
are due to thromboembolism distal to the site of intimal
injury. The outpouchings are sites of pseudoaneurysm
formation.
+ DIAGNOSIS: Arterial injury with distal
thromboembolization.
+ KEY FACTS
CLINICAL
• The clinical signs of an expanding pulsatile mass,
diminished blood pressure, or distal limb ischemia in a
trauma patient are indications of vascular injury until
proven otherwise.
• The most reliable clinical sign of arterial injury within
a limb is diminished or absent blood pressure. However,
in the setting of systemic hypotension, this finding
is difficult to evaluate.
• Hematoma and vascular occlusion are immediate
sequelae of arterial injury. Pseudoaneurysm and AV fistula
formation are potential delayed sequelae.
• Obvious arterial injuries in an unstable, hypotensive
patient are an indication for immediate surgical exploration
and repair.
• Although most arterial injuries are due to penetrating
trauma, injury can also result from nonpenetrating
trauma, including stretch injury. The latter is typically
seen following joint dislocations (e.g., posterior knee
dislocations) .
RADIOLOGIC
• The role of angiography in the setting of suspected
arterial injury is to determine the presence or absence
409
of injury (thereby minimizing the number of unnecessary
surgical explorations), define the type of injury,
and on occasion, temporize or definitively treat the
injury via endovascular therapy.
• Typically, two or more angiographic views are obtained
to decrease the chance of a false-negative study.
• The false-positive rate for angiography is 0% to 4%.
False-positive angiograms can be produced by the following
causes: ( 1 ) arteries seen on-end can be mistaken
for pseudoaneurysms, (2) inflow of unopacified blood
("streaming" effect) from collateral arteries can be mistaken
for intraluminal thrombus, ( 3 ) arterial spasm
induced by the catheter, guidewire, or contrast material
injection is mistaken for vasospasm related to trauma.
• The false-negative rate is 0% to 1 .8%. False-negative
angiograms can be due to: ( 1 ) use of only a single projection,
on which a site of injury is obscured by contrast
material; (2) wrong choice of contrast material
volume (i.e., too little) or injection rate (i.e., too
slow); ( 3 ) failure to selectively catheterize an artery
with a suspected abnormality; and (4) premature termination
of the imaging procedure. False-negative
studies therefore can be minimized by selective
catheterization of the vessel thought to be injured,
choice of an injection rate and volume that will completely
opacity the vessel, obtaining orthogonal views
of the region, and obtaining late images that will show
delayed clearance or extravasation of contrast material.
• The two most common findings in arterial injury are
occlusion and extravasation of contrast material. Arterial
occlusion can reflect either intimal injury (and subsequent
thrombus formation) or transmural disruption.
Other findings t11at can be seen include the presence of
an intimal flap, vasospasm, pseudo aneurysm formation,
AV fistula, distal embolization, intramural hematoma,
and displacement of vessels by adjacent hematoma.

Front 199

An 8-year-old boy with pleuritic chest pain and 39°C temperature.

Back 199

Hilar adenopathy: This diagnosis is incorrect because
the right hilum is seen as separate from the "mass. "
Therefore, this mass must b e anterior o r posterior in
the right hemithorax .
• Plasma cell granuloma (postinflammatory pseudotumor):
Plasma cell granuloma can present as a mass,
with calcification in up to 25% of cases. Children are
usually asymptomatic or have very minimal symptoms.
This is a possible diagnosis in this case, which cannot
be excluded on the basis of the radiographs, but it is a
relatively rare entity.
• Bronchopulmonary foregut malformation: Such
malformations-e.g., parenchymal bronchogenic cyst
or a pulmonary sequestration-are reasonable considerations
on the basis of the findings. Cystic adenomatoid
malformation is another malformation to be
considered, but it rarely presents in older children or
adults and is usually hyperlucent. Arteriovenous malformations
are usually multiple, with associated
enlarged arteries and veins.
• Primary pulmonary malignancy: Sarcomas and pulmonary
blastomas, the most likely primary tumors,
could produce these findings, but these lesions are
exceedingly rare .
• Metastasis: This is an unlikely diagnosis because there
is no history of malignancy. Furthermore, a single,
large metastasis would be unusual.
• Round pneumonia: Round pneumonia is a very common
cause of a pulmonary mass in children. This
entity is much more common than a bronchopulmonary
foregut malformation.
• Contusion: This diagnosis is not a reasonable consideration
because there is no history of trauma.
• Round atelectasis: Row1d atelectasis is a consideration
based on the shape of the opacity but is usually basilar
in location and is very rare in children.
• Pleural effusion caused by "pseudotumor": This
entity is unlikely because it is usually sharply defined at
some aspect in at least one projection.
• Hamartoma: This diagnosis is a consideration but is
usually asymptomatic and is relatively rare .
413
DIAGNOSIS: Round pneumonia in the superior
segment of the right lower lobe.
KEY FACTS
CLINICAL
• Almost all pulmonary masses in children are related
to infection ( e .g . , round pneumonia, plasma cell
granuloma ) .
• Round pneumonia i s a common cause o f pulmonary
mass in children.
• Round pneumonia is rare over 8 years of age.
• Streptococcus pneumoniae (pneumococcus) is the most
common organism responsibie for round pneumonia.
• Symptoms can be mild or nonspecific early in the clinical
course .
• With a typical clinical history and recognition of a
mass on imaging studies as round pneumonia, antibiotic
treatment can be started without further imaging.
• In cases in which the clinical information is unclear a
pulmonary mass can be conservatively followed with a
repeat chest radiograph in 24 to 48 hours. Round
pneumonia will typically become closer in appearance
to a lobar pneumonia at d1at time.

Front 200

A 14-month-old boy with a palpable abdominal mass.

Back 200

Hepatocellular carcinoma: This diagnosis is unlikely
because this neoplasm rarely occurs below the age of 2
years. Furthermore, frequently there is a history of
chronic liver disease.
• Hepatoblastoma: This is the most common malignant
primary liver tumor of childhood, usually occurring
before the age of 3 years. The young age of the patient
and inhomogeneous appearance of the mass in the present
case are consistent with this diagnosis.
• Mesenchymal hamartoma: This diagnosis is unlikely
because it is rare, cystic, and often exophytic, unlike
the case illustrated. The diagnosis is frequently made
by prenatal sonography.
• Hemangioendothelioma: This entity is the most
common symptomatic vascular lesion in infancy and
most common mesenchymal tumor of childhood. This
diagnosis is unlikely in the case illustrated because it
frequently contains large feeding vessels and areas of
hypointensity on T l -weighted images, corresponding
to fibrosis and hemosiderin deposition .
• Hepatic adenoma: These tumors are extremely rare in
young children. Furthermore, the lesion frequently
contains regions of high signal on Tl -weighted images
due to fatty change or hemorrhage. This finding is not
seen in the case illustrated, further making this diagnosis
an unlikely one.
+ DIAGNOSIS: Hepatoblastoma_
+ KEY FACTS
CLINICAL
• Hepatoblastoma is probably an infantile form of hepatocellular
carcinoma.
415
• This tumor primarily occurs before the age of 3 years
(median age: 1 year).
• A male-to-female predominance between 2 to 1 and 3
to 1 has been reported.
• The tumor is associated with Beckwith-Wiedemann
syndrome (i.e., hemihypertrophy and biliary atresia).
• Nearly all patients with this tumor have elevated serum
levels of alpha fetoprotein.
• Prognosis is usually good if there are no metastases
and the tumor is limited to the liver and is completely
resectable.
RADIOLOGIC
• Hepatoblastoma usually presents as a single mass.
However, multifocal involvement can sometimes occur.
• On contrast-enhanced CT examination, the mass does
not contrast-enhance to a large degree
• This tumor generally has heterogeneous, hyperintense
signal on T2-weighted MR!.
• Splaying of hepatic veins around the mass can be seen
occasionally.
• The sonographic appearance is that of a hypoechoic
mass with displacement of the hepatic arterial and portal
venous vessels by the tumor.
SUGGESTED READING
Boechat MI, Kangarloo H, Ortega J , et aI. Primary liver tumors in
children: Comparison of CT and M R imaging. Radiology
1 9 8 8 ; 1 69:727-732.
Finn JP, Hall-Craggs MA, Dicks-Mireaux C, et aI. Primary malignant
liver tumors in childhood: Assessment of resectability with
high field MR and comparison with CT. Pediatr Radiol
1 990;2 1 : 34-38 .
Pobiel RS, Bisset G B . Pictorial essay: I maging o f liver tumors i n the
infant and child. Pediatr Radiol 1 995;25 :495-506.

Front 201

A toddler with urinary retention and distended abdomen.

Back 201

DIFFERENTIAL DIAGNOSIS
• Ovarian teratoma: Any tumorous growth from the
ovary could grow to the size shown in this case. However,
extension around the sacrum is not a feature typically
seen in ovarian tumor, making this an unlikely
diagnosis.
• Abscess: This entity cannot be excluded on the basis
of imaging fIndings alone. However, it is an unlikely
diagnosis because the clinical history does not suggest
the presence of infectious process.
• Neuroblastoma (or ganglioneuroma): The location
and appearance of the mass are consistent with this
diagnosis. However, posterior encasement and direct
sacral involvement are not findings that would be
expected in pelvic neuroblastoma.
• Sacrococcygeal germ cell tumor (i.e., teratoma):
Teratoma is the best diagnosis, based on the presacral
and retrorectal location and, in particular, the encasement
of sacral segments.
• Anterior meningocele: This diagnosis is unlikely
because the mass is not cystic.
• Rhabdomyosarcoma: Because posterior sacral extension
would be unusual for rhabdomyosarcoma, this is
an unlikely diagnosis.
• Primary bone tumor: A prinlary bone tumor is not a
likely consideration because there is no bony destruction
and sacral involvement in this case is relatively minin1al.
• Gastrointestinal duplication: This diagnosis is
unlikely because rectal duplications are very rare and
extension to sacrum would not be expected.
• DIAGNOSIS: Malignant sacrococcygeal germ cell
tumor (teratoma).
KEY FACTS
CLINICAL
• Sacrococcygeal teratomas are relatively rare, with an
estimated prevalence of 1 in 3 5 ,000-40,000 births.
• The category of germ cell tumors includes teratomas,
choriocarcinomas, embryonal cell carcinomas, yolk sac
tumors, and mixed types.
• Teratomas are classified as mature, in1mature, or malignant.
Malignancy is rare in mature types.
• Treatment consists of chemotherapy and surgical
resection.
• Early diagnosis and surgical excision is indicated
because the incidence of malignant transformation
increases with advancing age.
417
• Four types of sacral teratomas have been described,
according to the internal and external components of
the mass:
Type 1: primarily external to the pelvis
Type 2: predominantly external to the pelvis with
intrapelvic component
Type 3: primarily intrapelvic with only a small
extrapelvic portion
Type 4: entirely presacral without extrapelvic extension
In general, the greater tlle intrapelvic component, the
greater the likelihood of malignancy.

Front 202

A I 5-year-old boy presents with fever, cough, abdominal pain, and diarrhea.

Back 202

Crohn's disease: This diffuse process could cause the
barium enema findings but would not explain the findings
in the upper abdomen and chest.
• Infectious colitis: Salmonella and Shigella enterocolitis
and amebiasis can cause abnormalities of the
ascending colon. These entities would be unlikely to
cause the degree of mucosal ulceration and nodularity
seen in the case presented. In addition, they would not
explain the findings on the chest radiograph and upper
abdomen CT scan.
• Appendicitis: The inflammatory process resulting
from appendicitis can involve the colon and terminal
ileum and result in wall thickening. It would be
unlikely, however, to cause mucosal destruction.
• Neutropenic colitis: This diagnosis is not a consideration
because the patient is not neutropenic.
• Hemorrhage or ischemic edema: This entity would
not be expected to cause the low attenuation adenopathy
and chest radiographic findings.
• Tuberculosis (TB): This entity provides a unifYing
diagnosis to explain the constellation of findings in the
chest, abdomen, and colon. TB could cause upper lobe
disease, fibrosis, and volume loss in the chest, as well
as the low attenuation of lymph nodes in the upper
abdomen. Furthermore, tuberculous involvement of
the colon can mimic Crohn's disease .
+ DIAGNOSIS: Tuberculosis.
+ KEY FACTS
CLINICAL
• Postprimary TB is rare in children who were infected
before 2 years of age. This entity is most commonly
seen when initial infection was in adolescence.
• Postprimary TB in the lungs can produce fibroreticular
or fibronodular opacities in the upper lobes. Superior
retraction of the hila, fibrosis of the upper lobes, traction
bronchiectasis, volume loss, and focal calcification
can result. Cavitation and apical pleural thickening can
also be seen. Lymphadenopathy is rare in children with
postprimary TB .
• In children, similar chest radiographic appearances can
be seen with histoplasmosis and atypical mycobacterial
infections. Cystic fibrosis can have a similar appearance
and distribution but increased lung volumes would be
expected.
• Gastrointestinal TB in industrialized countries is currently
most commonly due to Mycobacterium tuberculosis.
As a result of improved milk hygiene, M. bovis as
a gastrointestinal pathogen has been largely controlled.
419
• The most common sites of tuberculous involvement of
the gastrointestinal tract are the ileocecal region and
the ascending colon.
• The clinical symptoms of patients with colonic TB are
nonspecific and include diarrhea, abdominal pain,
weight loss, and fever.
• Colonic TB is commonly seen with either concurrent
or prior pulmonary TB, but pulmonary TB need not
be present.
• Diagnosis of gastrointestinal TB depends on biopsy or
segmental resection, because stool examination, cultures,
and colonoscopic examinations are frequently
nondiagnostic.

Front 203

A 5-year-old boy with a 2-month history of tibial pain and limp.

Back 203

The major considerations in this differential are the small,
round, blue cell tumors of childllood. All may present
with a permeative pattern and a wide zone of transition.
• Metastases: Especially those due to neuroblastoma
and rhabdomyosarcoma.
• Leukemia and lymphoma: This is a reasonable consideration
because the lymphoproliferative malignancies
are the most common childllood cancer. Bone abnormalities
in leukemia are fairly common (osteoporosis,
metaphyseal lucencies, periosteal reaction, sclerotic or
lucent lesions, permeative patterns); the involvement is
most often multifocal and symmetrical, however.
Lymphoma may have an identical appearance.
• Ewing's sarcoma: A good consideration based on the
history and radiographic findings.
• Primitive neuroectodermal tumors (PNETs): Both
central nervous system ( i . e . , medulloblastoma) and
non-central nervous system ( includes Askin's tumor of
the chest wall) types of metastatic PNETs can present
with the above history and fmdings, usually in older
children and adolescents.
Considerations other than the small, round, blue cell
tumors include:
• Osteomyelitis: It may be impossible to differentiate
osteomyelitis from Ewing's sarcoma clinically and
radiologically.
• Eosinophilic granuloma: This entity has a large variety
of appearances ( classically a lucent defect) that
include an aggressive appearance such as this one .
+DIAGNOSIS: Ewing's sarcoma.
+ KEY FACTS
CLINICAL
• Of the small, round, blue cell tumors discussed above,
Ewing's sarcoma and PNET tumors can be very difficult
to distinguish clinically, radiographically, and histologically.
Electron microscopy may be necessary to
demonstrate neural substances or structures not fowld
with Ewing's sarcoma.
• Ewing's sarcoma occurs most commonly in the second
half of the first decade of life and the first half of the
second decade, a slightly younger age distribution than
that of osteosarcoma.
• Males are affected slightly more commonly than
females ( 3 to 2 ) .
• There is a distinct predilection for whites; Ewing's sarcoma
is uncommon in Asians and African-Americans.
• The clinical presentation may be identical with that of
osteomyelitis, with systemic symptoms of fever, elevated
sedimentation rate, and leukocytosis.
421
• Metastatic spread is most often to other bones and to
the IWlgS, being present in between 1 0% and 30% of
cases at time of diagnosis.
• Poor prognostic indicators include large size ( >8 cm),
central location, nonresectability, older age, and elevated
erythrocyte sedimentation rate and leukocyte
count at time of presentation.
• Survival rates have increased significantly with use of
preoperative chemotherapy.

Front 204

A 6-year-old girl with fever, cough, and acute stridor.

Back 204

Tracheal foreign body: This diagnosis is a possible
consideration, but there is no history of aspiration of a
foreign body.
• Papilloma: Papillomas do not usually present with
acute stridor and fever; rather, chronic hoarseness is
more typical. Furthermore, the opacities in this case
are not mass-like, as would be expected with papillomas.
• Tracheal mucus: This diagnosis is a reasonable consideration
that cannot be excluded on the basis of the
present study.
• Bacterial tracheitis: This diagnosis is consistent with
the history and radiographic findings.
• Epiglottitis: The history presented in this case is typical
for epiglottitis, but the epiglottis is normal in
appearance.
• Croup (laryngotracheobronchitis): Croup usually
occurs in children age 6 months to 3 years, much
younger than the child in this case. Furthermore, narrowing
of the subglottic trachea ("steeple sign"),
which would be expected in croup, is not present.
• Granuloma: This is an unlikely diagnosis because
there is no history of previous tracheal intubation or
other trauma.
• Retropharyngeal abscess: The retropharyngeal soft
tissues are normal in this case, excluding the diagnosis
of a retropharyngeal abscess as a cause of the stridor.
+ DIAGNOSIS: Bacterial tracheitis (also known as
membranous croup or membranous laryngotracheobronchitis
).
+ KEY FACTS
CLINICAL
• Tracheitis is rare compared with other infectious causes
of stridor (e.g., retropharyngeal abscess, croup, or
epiglotti tis ).
• Acute onset of stridor is typical.
• The mean age at presentation is 4 years old, but bacterial
tracheitis can be seen at any age.
• Prompt recognition is important, because membranes
can obstruct the airway acutely.
423
• Infection is bacterial in origin. Staphyloccus aureus is
the most common agent, but occasionally Streptococcus
pneumoniae and Haemophilus influenza can produce
the infection. Tracheitis can also occur as a superinfection
following a viral upper airway process.
• Flexible endoscopy to confirm the diagnosis is indicated
if clinical or radiographic findings suggest tracheitis.
• Management includes supportive care ( humidification,
antibiotics, suctioning). "Elective" intubation may be
necessary to protect the airway from obstruction.

Front 205

A 5 -week-old girl with persistent, nonbilious vomiting. There is no history
of diarrhea or fever.

Back 205

Gastroesophageal reflux: The patient's history makes
this diagnosis a possibility. However, no reflux of contrast
material is seen at fluoroscopy. Instead, a pyloric
abnormality is visible on upper gastrointestinal series
and sonography.
• Pylorospasm: This is an unlikely diagnosis based on
the clinical history and imaging findings. Pylorospasm
can be seen in patients who are extremely agitated,
dehydrated, or septic, or who have adrenogenital syndrome,
none of which appeared in this patient.
Furthermore, pylorospasm is unlikely to persist
throughout the series of examinations.
• Pyloric channel ulcer: This entity could account for
the delayed gastric emptying and vomiting. However,
no ulcer is identified on the imaging studies shown .
• Antral web: Antral web is another cause of delayed
gastric emptying and vomiting. Again, no evidence of
an obstructing web is seen on the imaging studies.
• Hypertrophic pyloric stenosis (HPS): This entity is
the best diagnosis based on the history and imaging
findings. The sonographic findings of concentric thickening
of the pyloric muscularis and elongation of the
pyloric channel are typical for this entity. The multiple
thin tracks of barium visible in the pyloric channel on
the UGI series represent folds of mucosa in a narrowed
channel, further evidence of HPS.
• Malrotation with obstruction: This diagnosis is
untenable for a number of reasons. First, in malrotation
the site of obstruction is the duodenum, not the
pylorus. In the first month of life the obstruction from
malrotation is due to midgut volvulus. With malrotation
later in infancy and childhood, Ladd bands (peritoneal
reflections) cause obstruction and vomiting as
they cross the duodenum and fix the malpositioned
cecum. Second, volvulus typically presents with bilious
vomiting, and non bilious vomiting is rare.
• Congenital atresia: Congenital atresia presents clinically
much earlier than the patient in the case illustrated.
Duodenal atresia is evident at birth with a
radiographic "double bubble" due to gas-distended
stomach and proximal duodenum. Ileal atresia is evident
at birth with distension and vomiting, which is
often bilious.
DIAGNOSIS: Hypertrophic pyloric stenosis.
+ KEY FACTS
CLINICAL
• HPS is the most common infantile gastrointestinal
abnormality requiring surgery, typically occurring in
white boys at a peak age of 4 to 8 weeks.
• The clinical presentation is that of non bilious vomiting,
which gradually increases in severity from low-
425
velocity regurgitation to projectile vomiting. Weight
loss, dehydration, and hypochloremic acidosis can
occur secondarily. Nonetheless, most patients appear
healthy but hungry.
• A palpable thickened pylorus ( "olive" ) in the epigastrium
is pathognomonic but is usually detectable only
by the trained examiner. When an olive is present in
the setting of suspected H PS, no preoperative imaging
is necessary.
• The treatment is pyloromyotomy. Although spontaneous
regression of muscular hypertrophy can occur
without surgery, nonoperative therapy is difficult to justifY
given quick, safe, and effective surgical treatment.
• A 1 9 8 1 report in the surgical literature reported an
increase in genitourinary abnormalities in children
with HPS and recommended routine renal evaluation.
More recent studies have not shown such an increased
prevalence.

Front 206

A I -month -old boy with torticollis and a firm mass on the right side of the neck

Back 206

The differential diagnosis for a mass in this specific location
with this clinical history and these sonographic features
is very limited. However, a differential diagnosis for
a mass in the neck of an infant will be reviewed.
• Branchial cleft cyst: This is an unlikely consideration
because no cystic components are seen in the mass.
These usually arise from the second branchial cleft
( occasionally the third) . These lesions are typically
located anterior to the sternocleidomastoid and may
displace it posteriorly. Cysts are also fluctuant and not
firm unless inflamed. These lesions usually present later
in childhood, often with inflammation.
• Lymphangioma/hemangioma: These lesions most
often arise from the posterior triangle, dorsal to the
sternocleidomastoid. Typically, lymphangiomas/
hemangiomas do not displace adjacent structures, but
rather insinuate themselves between other structures.
Typically, there will be cystic components; those with
large cystic components are referred to as cystic hygromas.
For these reasons, a lymphangioma is not a good
consideration.
• Thyroglossal duct cyst: The location excludes this
diagnosis. These lesions are located in the midline
from the base of the tongue to the thyroid ( many are
in the hyoid bone) . As with branchial cleft cysts, imaging
shows a purely cystic lesion unless infection or
internal hemorrhage has occurred.
• Adenopathy/adenitis: Enlarged lymph nodes have a
characteristic well-defined, hypoechoic appearance.
Furthermore, adenitis is rarely seen in infants under
the age of 6 months.
• Malignancy: Malignancy is rare at this age. The three
most common malignancies seen in the neck in a child
are rhabdomyosarcoma, lymphoma, and neuroblastoma.
Rhabdomyosarcoma is a consideration in this case
because the lesion arises in muscle. The other two lesions
are excluded based on the intramuscular location.
• Ectopic cervical thymus: This is a solid mass that may
not be contiguous with the normal thymus. However,
ectopic thymic tissue would be separable from the sternocleidomastoid
muscle. Unlike the normal thymus,
ectopic thymus can cause airway symptoms but is usually
asymptomatic.
427
Fibromatosis colli: The clinical history of torticollis
in a young infant and the sonographic finding of a
mass that is isoechoic to muscle are typical of this
diagnosis.
+ DIAGNOSIS: Fibromatosis colli.
+ KEY FACTS
CLINICAL
• Fibromatosis colli presents as a mass in the sternocleidomastoid
2 or more weeks following birth. Frequently,
a history of birth trauma is present.
• Fibromatosis colli typically presents with torticollis,
chin pointed away from the side of the palpable mass,
and a firm, nontender mass along the course of the
sternocleidomastoid.
• Management is typically conservative, with passive
range of motion therapy or no therapy.
• The mass usually spontaneously regresses over a 4- to
8-month interval . Only very rarely is surgery required.

Front 207

A 5-year-old boy with recurrent right lower-lobe pneumonia.

Back 207

Pulmonary sequestration: This diagnosis is the most
likely, given the history of recurrent infection, lowerlobe
location, and systemic arterial supply.
• Bronchogenic cyst: This diagnosis is w1Likely because
a systemic vascular supply would not be expected to be
present.
• Arteriovenous malformation (AVM): Pulmonary
AVMs frequently have an appearance of multiple,
mass-like lesions witl1 prominent feeding arteries,
which can be of systemic origin. However, me absence
of draining veins in me cases illustrated makes AVM an
unlikely diagnosis.
• Recurrent pneumonia/atelectasis from an endobronchial
or exobronchial lesion: The clinical history
and chest radiograph are consistent wim tlUs diagnosis.
Furmermore, a site of recurrent infection can acquire a
systemic arterial supply (considered an acquired intralobar
sequestration [see below ] ) . However, it is rare in
me setting of pneumonia and is not seen wim atelectasis.
Anomer form of pnewnonia, so-called round pneumonia,
is a consideration based on me findings on me
chest radiograph in Figure 8-9A but is not compatible
wim me MRI of me chest in Figure 8-9B.
• Pulmonary neoplasm: This is an unlikely diagnosis
because mese are very rare lesions in children and
blood supply from me aorta is not a typical feature .
• Diaphragmatic hernia/eventration: The radiographic
appearance of mis lesion can mimic mat of
sequestration in some cases, but small diaphragmatic
abnormalities are generally clinically silent. Diaphragmatic
abnormalities would be expected to be well
defined, W1like me appearance of me lesion in Figure
8 -9A.
+ DIAGNOSIS: Pulmonary sequestration ( intralobar
type).
+ KEY FACTS
CLINICAL
• The term sequestration refers to a nonfunctioning pulmonary
parenchymal abnormality mat lacks normal
tracheobronchial communication and has anomalous
systemic ( ramer man pulmonary) arterial supply.
Venous drainage may also be via systemic veins ramer
man pulmonary veins.
• Traditionally, intralobar (i.e., no separate pleura) and
extralobar (i.e., having a separate pleural investment)
types have been distinguished. Sequestration is one of
me continuum of bronchopulmonary foregut malformations
(variable contribution of anomalies of lung,
airway, and vasculature ) .
• Modes o f presentation generally differ according to me
age at time of diagnosis.
429
• In me prenatal period, me diagnosis is based on me
finding of an echogenic chest mass at sonography.
• The clinical presentation in me neonatal period consists
of respiratory distress.
• In a child ( and occasionally an adult), me clinical presentation
is mat of recurrent pulmonary infections.
• More tl1an half of sequestrations present before adulthood.
• Sequestration can occasionally present in an infant or
small child as a murmur and congestive heart failure
due to me arteriovenous shunting.
• The intralobar type is me more common type and can
be congenital or acquired. Most of mese are lower
lobe in location, wim two-tlUrds located on me left.
Drainage is usually via me pulmonary veins.
• The extralobar type also usually occurs in me lower
lobe and is on me left in 90% of cases. Drainage is typically
wough systemic veins. Fifty percent of cases
have associated anomalies (heart disease, diaphragmatic
hernias, gastrointestinal and omer pulmonary abnormalities).
Most extralobar sequestrations are discovered
wiiliin me first year of life .
• Treatment for all pulmonary sequestrations i s surgical
excision.

Front 208

A full-term infant being evaluated for an abnormality seen on prenatal ultrasound.

Back 208

Severe hydronephrosis or obstructed duplication:
This diagnosis is unlikely because the cystic spaces
would be expected to communicate, unlike in the case
presented. Furthermore, if a distal obstruction was
present, a dilated ureter would be expected to be seen.
• Ureteropelvic junction obstruction: Again, the cystic
spaces do not communicate with a centrally located,
dilated renal pelvis, making this an unlikely diagnosis.
• Cystic Wilms' tumor or other renal tumor:
Antenatal and congenital renal tumors are rare.
Multilocular cystic nephroma is a lesion that could be
considered in this case. The presence of a rim of
functional renal tissue on nuclear imaging ( not
present in this case) would make this a more likely
diagnosis.
• Multicystic dysplastic kidney (MCDK): MCDK is
the best diagnosis based on the fact that tIllS entity is
relatively common, the cysts are interconnecting, and
functioning renal tissue is absent on the nuclear medicine
study.
+ DIAGNOSIS: Multicystic dysplastic kidney.
+ KEY FACTS
CLINICAL
• MCDK is the second most common abdonlinal mass
in neonates, second only to hydronephrosis.
• MCDK is the most common palpable abdonlinal mass
on the first day of life . An increasing number of cases
are now initially seen on prenatal ultrasound and confirmed
with additional imaging studies in infancy.
• The etiology of MCDK is thought to be atresia of the
ureteric bud or failure of the ureteric bud to meet and
induce the metanephric blastema in utero.
• Approximately one-third of patients with MCDK have
contralateral renal abnormalities, most commonly
ureteropelvic junction obstruction or reflux.
• Because the kidney involved by MCDK is nonfunctional,
early detection and treatment of contralateral
abnormalities are important to preserve function in the
single functioning kidney.
431
RADIOLOGIC
• If the ureter alone is atretic, the hydronephrotic form
of MCDK (which is rare ) results with a dilated renal
pelvis and potentially interconnecting cysts.
• More commonly, the entire renal pelvis and proximal
ureter are atretic, resulting in the pelvoinfundibular
form of MCDK, as seen in the case illustrated here.
• Segmental forms of MCDK have also been reported.
• Without drainage of urine, the glomeruli become dysplastic
and the tubules atrophy, forming variably sized,
fluid-filled cysts that do not communicate. There may
be a thin rim of cortical tissue with hydronephrosis. In
MCDK, the scattered parenchyma is echogenic and
not cortical in distribution .
• Functional studies of the kidney can be obtained using
Tc-99m MAG-3, Tc-99m DTPA (diethylenetriamine
pentaacetic acid), or occasionally, other renal agents.
Early images or blood flow images can show faint
radio tracer activity initially, solely reflecting perfusion
of the dysplastic tissue . Delayed images show complete
absence of tracer activity in MCDK, as opposed to
gradual accumulation of tracer activity in obstructed
kidneys.

Front 209

An otherwise healthy I -month-old girl with mild tachypnea.

Back 209

Congestive heart failure: The heart is not enlarged
and there is no pleural effusion, as would be expected
with congestive heart failure.
• Viral pneumonitis: This diagnosis should be considered
on the basis of hyperinflation with interstitial
opacities. However, the patient is only minimally
symptomatic given the degree of radiographic abnormality,
making this diagnosis unlikely.
• Chlamydia pneumonia: Neonatal conjunctivitis
( absent in this case) is frequently, but not invariably,
present. The radiographic findings are compatible with
this diagnosis.
• Noncardiac causes of pulmonary edema: The clinical
data in this case (e.g., the absence of sepsis) do not
support the diagnosis of noncardiac edema. Primary
pulmonary lymphangiectasia, another potential cause
of noncardiac pulmonary edema, is usually quite evident
earlier in infancy than in the case illustrated, making
this diagnosis unlikely.
• Delayed-onset group B streptococcal pneumonia:
This diagnosis is a possible consideration based on the
radiographic findings. However, patients are usually
quite ill. The clinical symptoms in the case illustrated,
which are minimal, do not support this diagnosis.
+ DIAGNOSIS: Chlamydia pneumonia (congenitally
acquired).
+ KEY FACTS
CLINICAL
• Chlamydia pneumonia is a congenitally acquired infection
due to Chlamydia trachomatis, an obligate intracellular
parasite with some features of bacteria.
• A history of neonatal conjunctivitis is present in about
50% of cases. Neonatal rhinitis is another associated
feature.
433
• Symptoms occur beginning at 1 to 3 months, typically
at 6 weeks of age.
• Clinical signs include minimal tachypnea, hypoxemia,
and mild or absent fever. The radiographic abnormalities
are often more impressive than the clinical features.
• Rhinorrhea and "staccato" cough are often present.
• Chlamydia is the most common cause of afebrile interstitial
pneumonia in infants.
• The diagnosis can be made using a fluorescent antibody
test performed on a nasal swab specimen.
• The standard treatment is erythromycin. The infection
usually responds well to antibiotic treatment.
• Patients with Chlamydia pneumonia have a higher
incidence of subsequent chronic respiratory problems
compared to the general population.

Front 210

A 2-year-old child who refuses to bear weight

Back 210

Nonaccidental trauma (infant and child abuse):
Tlus diagnosis i s a likely consideration given the types
of fractures in both cases. The clinical information in
any individual case is important to rule out other entities
that can mimic nonaccidental trauma.
• Accidental trauma: "Corner" fractures would not be
expected to occur from accidental trauma resulting
from activities in which a 2 -year-old typically engages.
Accidental injury is not a consideration for a fracture
of this type and location in an infant who has not
reached the age of walking (see Figure 8 - 1 2 B ) .
• Osteogenesis imperfecta (01): The presence of multiple
fractures raises this entity as a possible diagnosis.
In both cases illustrated above, there was a lack of clinical
features ( e.g., blue sclerae, deafness, poor dentition)
that can be seen in 01.
• Menkes' syndrome: The cliIucal history in both of the
cases illustrated excludes this diagnosis because patients
with this syndrome have mental retardation and die in
infancy.
• Metaphyseal irregularity as a normal variant: This
variant is seen at the metaphyses as a "lip" of bone that
is continuous with the cortical bone. However, if the
lip is not continuous ( as in both of the cases illustrated),
a fracture is present.
+ DIAGNOSIS: Child abuse (nonaccidental
trauma).
+ KEY FACTS
CLINICAL
• In addition to the multiple types of skeletal injuries
seen in the setting of abuse, central nervous system
( CNS ) injury (e.g., subdural hematoma, diffuse
edema, diffuse infarction from hypoxia, and parenchymal
hemorrhage) can be present.
• The mechanism for these CNS injuries is currently
thought to be impact against a soft object in combination
with shaking, rather than shaking alone ( as was
previously thought) .
• With respect to skeletal injuries, rib fractures are more
common in children < l year old, whereas diaphyseal
injuries are more common in those > 1 year old. This
fact reflects the manner in which the child is typically
held during the traumatic event.
• Direct blows to the abdomen most frequently result in
duodenal hematoma, pancreatitis (with its attendant
complications), and hepatic and splenic injuries.
• The diagnosis is established with a combination of history
(i.e., incompatibility of the reported history in
relation to the type and extent of injuries), physical
findings (e.g., burns, hand marks, sexual abuse, preretinal
hemorrhages), and radiographic findings.
435
• A major diagnostic consideration is 01, in which a
family history of fractures, deafness, blue sclerae, and
poor dentition can be elicited. If necessary, the diagnosis
can be confirmed with a skin biopsy demonstrating
a collagen synthesis deficiency.
• Another diagnostic consideration is Menkes' syndrome,
a rare neurodegenerative disorder due to a defect in
copper metabolism, leading to death within the first year
of life. These patients have sparse, brittle hair, which
accounts for the designation "kinky hair syndrome."

Front 211

A neonate with low hematocrit following traumatic delivery.

Back 211

Neuroblastoma: Congenital nemoblastoma is more
often solid than cystic and would not be expected to
change from soLid to cystic without therapy
(chemotherapy or biopsy producing internal hemorrhage
). Neuroblastoma also tends to distort the shape
of the adrenal gland. For these reasons, this is an
unlikely diagnosis.
• Other retroperitoneal tumors-e.g., lymphangioma,
teratoma: More fluid-filled spaces and calcification
are typical of these tumors. They are very rarely
located in the retroperitoneum, making them further
unlikely considerations in this case.
• Perinephric abscess: A phlegmon or abscess could
have mixed echogenicity similar to this lesion, but
there is no history of infection. Fmthermore, rather
than a mass adjacent to the adrenal gland (as would be
expected in a perinephric abscess), in this case it is the
adrenal gland itself that is enlarged and hypoechoic.
• Congenital adrenal hyperplasia: This entity should
involve the adrenal glands bilaterally. Biochemical
abnormalities, which are not present in the case illustrated,
are helpful in supporting the diagnosis of congenital
adrenal hyperplasia. Therefore, this is an
unlikely diagnosis.
• Adrenal hemorrhage: This process is the most Likely
diagnosis in this case based on the mixed echogenicity,
retention of shape of the glands, and change in echotextme
over a relatively short period of time.
+ DIAGNOSIS: Neonatal adrenal hemorrhage.
+ KEY FACTS
CLINICAL
• Spontaneous adrenal hemorrhage occurs relatively
commonly in newborn infants and is occasionally
detected in utero.
• Predisposing factors include perinatal stress, traumatic
birth, hypoxia, and sepsis. Hemorrhage also occurs
with increased frequency in large infants and infants of
diabetic mothers.
437
• Large hemorrhages can present with shock or a palpable
mass, while smaller hemorrhages cause mild anemia
or jaw1dice. Biochemical abnormalities are seldom present
in either the acute or convalescent phase.
• Adrenal hemorrhage is more common on the left side
and is seen bilaterally in approximately 1 0% of cases.
• Complications are uncommon and include renal vein
thrombosis (especially on the left side ), secondary
infection/abscess, and dystrophic calcification .

Front 212

A term neonate with mild tachypnea but no cyanosis.

Back 212

Transient tachypnea of the newborn (TIN): This is
the most likely diagnosis in light of the clinical history
of mild tachypnea and the rapid resolution of radiologic
findings.
• Respiratory distress due to surfactant deficiency
(respiratory distress syndrome, hyaline membrane
disease): This entity is an unlikely diagnosis because,
in this condition, the lung volumes are typically
reduced ( in an infant who is not intubated) and the
presence of pleural fluid is very rare. The radiographic
pattern with surfactant deficiency is that of a diffuse,
fme ( "ground glass" ), granular appearance, unlike the
case illustrated . Furthermore, this entity is seen nearly
exclusively in preterm infants.
• Meconium aspiration: Generally more patchy opacities
(atelectasis) with focal air trapping is seen in this
disease process, rather than the streaky opacities seen
in the case illustrated.
• Congestive heart failure: This is an unlikely diagnosis
because the heart size is typically enlarged in congestive
heart failure, unlike the case shown here.
• Neonatal pneumonia: This entity can initially have a
similar radiographic appearance to the case shown
here, but pneumonia does not spontaneously resolve
in 48 hours. Furthermore, clinical information supporting
infection (e.g., prolonged rupture of membranes,
maternal fever, infant leukocytosis or
leukopenia, infected amniotic fluid) was not present in
the case illustrated.
DIAGNOSIS: Transient tachypnea of the newborn
(retained fetal lung fluid, wet-lung syndrome,
persistent pulmonary edema).
+ KEY FACTS
CLINICAL
• The radiographic and clinical findings of TIN are due
to delayed clearance of fetal lung fluid from the pulmonary
interstitium.
439
• TIN is probably the most common cause of neonatal
respiratory distress.
• This entity is slightly more common in males.
• Risk factors for TIN include prolonged labor, cesarean
section, precipitous delivery, maternal diabetes, neonatal
hypoproteinemia, and maternal administration of
hypotonic fluid.
• Tachypnea is present within the first few hours of life.
Respiratory distress peaks by 24 hours and is nearly
always resolved by 2 to 3 days. Otl1er clinical features
include occasional grunting, sternal and intercostal
retractions, and mild cyanosis.
• Treatment is conservative and usually consists of an
oxygen hood. Antibiotics may be given if it is unclear
whether infection is the cause of symptoms.
• Neonatal pneumonia ( group B streptococcus ), hyaline
membrane disease, meconium aspiration, asphyxia,
congestive heart failure, and TIN can have similar
clinical presentations in the first few hours of life.

Front 213

A 9-year-old boy who was involved as a pedestrian in a motor vehicle accident.

Back 213

Hypoperfusion complex: This entity is usually seen in
the setting of post-traumatic hypovolemic shock and
has the imaging findings of ( 1 ) abnormally increased
contrast enhancement of the pancreas, kidneys, and
bowel wall; ( 2 ) fluid-filled bowel loops with free peritoneal
fluid; and ( 3 ) a small aorta and vena cava due to
the reduced blood volume. However, usually more
intense contrast enhancement of bowel wall and
mesentery is seen than in the present case. The diminished
caliber of the major abdominal vessels seen in
hypoperfusion complex is not seen in the present case.
• Uncomplicated hemoperitoneum: This diagnosis is
unlikely. Although in the case illustrated there is free
intraperitoneal fluid that could be blood (or urine and
bile, since these have the same appearance ), bowel wall
contrast enhancement would not be expected in
uncomplicated hemoperitoneum.
• Pancreatic trauma: This diagnosis is unlikely based on
the imaging findings. Pancreatic fractures can be clinically
undetected and may present with bowel dilatation
secondary to ileus, but the resultant fluid collections
would be expected to be retroperitoneal. Furthermore,
bowel wall contrast enhancement would not be
expected.
• Bowel and mesenteric injury: This diagnosis is most
likely, given the free intraperitoneal fluid and bowel
wall contrast enhancement in the setting of a normal
caliber aorta and inferior vena cava.
+ DIAGNOSIS: Bowel perforation (without evidence
of pneumoperitoneum).
KEY FACTS
CLINICAL
• Either or both substantial bowel and mesenteric
trauma are found in 3% to 5% of children who have
blunt abdominal trauma.
441
• The clinical signs of bowel injury are nonspecific but
include abdominal tenderness and guarding, rebound
tenderness, and absent bowel sounds.
• Undetected injuries of the bowel result in markedly
increased morbidity and mortality.
RADIOLOGIC
• The definitive CT signs of bowel perforation are the
presence of pneumoperitoneum and extravasated oral
contrast material. Pneumoperitoneum occurs in only
30% to 40% of patients and can be subtle. Extravasation
of intravenous contrast material is rarely seen.
• Typical CT findings include bowel wall thickening,
contrast enhancement, and otherwise unexplained
peritoneal fluid.
+ SUGGESTED READING
Bulas DI, Taylor GA, Eichelberger MR. The value of CT in detecting
bowel perforation in children after blunt abdominal trauma.
AJR Am J Roentgenol 1 9 89 ; 1 5 3 : 56 1-564.
Gay SB, Sistrom CL. Computed tomographic evaluation of blunt
abdominal trauma. Radiol Clin North Am 1992;30 :367-388.
Nghiem HV, Jeffrey RB Jr, Mindelzun RE. CT of blunt trauma to
the bowel and mesentery. AJR Am J Roentgenol 1 993;
1 60:53-5 8.

Front 214

An asymptomatic 8-year-old girl with human immunodeficiency virus (HIV).

Back 214

Pneumocystis carinii pneumonia (PCP): This diagnosis
is an unlikely choice because the patient is
asymptomatic. PCP can present with a variety of
abnormalities. The most often described are interstitial
lung disease (with progression to diffuse airspace disease)
and focal consolidation.
• Cytomegalovirus ( CMV) pneumonitis: The radiographic
appearance of this disorder is indistinguishable
from PCP. As with PCP, CMV pneumonitis
would be unusual in an asymptomatic patient.
• Tuberculosis (TB): Although a miliary pattern can
occur with TB ( predominately Mycobacterium avium
intracellulare), the patient would be expected to be
symptomatic, with acute, rapidly progressive radiographic
changes.
• Lymphocytic interstitial pneumonitis (LIP): LIP is
the best diagnosis in this case because the patient is
asymptomatic, and a nodular interstitial disease pattern
and hilar adenopathy, common findings in LIP, are
present. Heart enlargement can be seen in patients
with LIP secondary to HIV cardiomyopathy.
• Other opportunistic infections: The radiographic
pattern may be highly variable. Nodular changes or
focal or diffuse airspace disease can be seen. However,
the patient would be expected to be symptomatic.
• Other interstitial pneumonitis with fibrosis:
Interstitial disease is common in HIV-positive patients,
but the pattern seen in the above patient is more reticular
and the lung volumes reduced to a greater degree
than would be expected.
DIAGNOSIS: Lymphocytic interstitial pneumonitis.
+ KEY FACTS
CLINICAL
• Pulmonary manifestations are common in pediatric
HIV infection. LIP and PCP are the most common
pulmonary disorders.
• LIP is a lymphoid response to HIV infection in which
lymphoid hypertrophy and plasma cells are found in
the alveolar and septal interstitium and in subpleural
and peribronchial locations. A more general term for
this ( and other) patterns of lymphoid hyperplasia is
pulmonary lymphoid hyperplasia.
443
• LIP is generally seen in HIV-positive children, but in
about 1 5% of cases is seen in children with other
immune-related disorders-e .g., primary immunodeficiencies
and renal transplant recipients.
• Children with LIP can be relatively asymptomatic.
When symptomatic, HIV-positive children are treated
initially with adjustment in their antiviral therapy.
Other therapy, primarily for 110n- HIV children, is
immune-system mediating agents (i.e., corticosteroids
) .
• Digital clubbing can occur, but hypertrophic pulmonary
osteoarthropathy is very unusual.
• Bronchoscopy and lavage do not help to establish the
diagnosis of LIP. Furthermore, open biopsy is being
performed less frequently than in the past for diagnosis.
Instead, when typical radiologic changes (see
below) develop in an asymptomatic, HIV-positive
child, the diagnosis is presumed to be LIP.
• There is a strong association of LIP and positive titers
to Epstein- Barr virus.

Front 215

A 2-year-old boy found to have a palpable abdominal mass at a routine physical
examination.

Back 215

Severe hydronephrosis or obstructed duplication:
The cystic spaces would be expected to communicate in
these entities and more renal parenchyma should be evident
than is seen in the case illustrated. Furthermore,
with distal obstruction, a dilated ureter would be
expected.
• Multicystic dysplastic kidney (MCDK): This diagnosis
is a reasonable consideration, but usually more
parenchymal tissue is seen between the cysts with
MCDK than is seen in this case (see Case 1 0 ) .
• Cystic Wilms' tumor: This diagnosis adequately fits
the imaging findings and would be more strongly
favored if there were a mass extending into the renal
vein or vena cava.
• Mesoblastic nephroma: These tumors are typically
solid, not cystic, making this an wilikely diagnosis.
• Clear cell sarcoma, rhabdoid tumor, or renal cell
carcinoma: Cysts may be present in all of these twnors,
but there are usually solid components. Renal cell carcinoma,
however, is not seen in children of this age.
• Multilocular cystic nephroma (MLCN): The clinical
presentation of a multicystic renal mass in an otherwise
asymptomatic young boy is typical of this entity, making
this the most likely diagnosis.
DIAGNOSIS: Multilocular cystic nephroma
(without primitive blastemal elements).
KEY FACTS
CLINICAL
• MLCN typically presents as a painless mass in children
between 3 months and 4 years of age. Boys are
affected twice as often as girls. A second peak in incidence
is noted in the third and fourth decade, at
which point there is a female-to-male ratio of 8 to 1 .
• Rapid development of a mass, hematuria, pain, and
infection are less common clinical features.
445
• These tumors are not familial, nor are they associated
with other cystic lesions in abdominal viscera.
• Two histologic patterns are recognized: cystic
nephroma, which does not contain blastemal cells in
septa, and cystic, partially differentiated nephroblastoma,
which has nodular solid elements containing
blastemal or other embryonal elements. Both entities
are managed in the same manner.
• Lesions are benign but are generally excised because
they can be indistinguishable from some malignant
renal neoplasms and for relief of mass effect. Local
recurrence is rare and is seen with those tumors with
primitive blastemal elements.
RADIOLOGIC
• MLCN is typically very large, is well-encapsulated by
fibrous tissue, and contains cysts of varying sizes and
wall thickness. The walls generally contrast-enhance on
CT. The two histologic types of MLCN are indistinguishable
radiographically.
• These tumors may be segmental or involve the entire
kidney

Front 216

A child with short stature and multiple fractures

Back 216

Osteogenesis imperfecta (01): Osteopenia, multiple
fractures, bony deformity, and gracile bones are the
classic features of this disorder and are well illustrated
in these two patients.
• Child abuse: Radiographically, there are several features
that distinguish 01 from child abuse. With 01,
the bones are typically osteopenic, and wormian (intrasutural)
bones may be present. Furthermore, the metaphyseal
"corner" fractures of child abuse are not seen.
The remaining entities are usually not difficult to differentiate
from 01 but share the feature of osteopenia,
consequently increasing the risk of fracture.
• Menkes' disease: This disorder of copper metabolism
has radiographic features similar to those of scurvy and
child abuse. Metaphyseal spurring, dense metaphyses,
and periosteal reaction are features of Menkes' disease
that are not seen in O r .
• Rickets: Flaring, irregularity o f t11e metaphyses, and
widening of the physes are features of rickets that are
not seen in O r .
• Hypophosphatasia: Patients witl1 hypophosphatasia
are severely osteopenic ( like patients with 01), but
they also have craniosynostosis, lucencies in the distal
femurs, and rachitic changes.
• Homocystinuria: AB in 01, multiple compression fractures
of the spine can be seen in homocystinuria.
Radiographic manifestations seen in homocystinuria
but not 01 include epiphyseal flattening and bony
spicules extending from the metaphysis into the physis.
+ DIAGNOSIS: Osteogenesis imperfecta (type 3,
Figure 8 - 1 8A; type 1, Figure 8- 18B).
+ KEY FACTS
CLINICAL
• A deficiency of type I collagen in 01 patients is
responsible for the increased bone fragility. Other clinical
manifestations include blue sclerae, thin skin, hernias,
early vascular calcifications, lax joints, bleeding,
cardiac lesions, deafuess, and poor dentition .
• Type 1 01 (01 tarda) : Despite its name, a small percentage
of patients can have fractures at birth. The
inheritance pattern is autosomal dominant. AU of these
447
patients have blue sclerae. Some have either or both
presenile conductive hearing loss and dentinogenesis
imperfecta.
• Type 2 01: This subtype was previously known as 01
congenita; the inheritance pattern is usually autosomal
recessive . Survival is very short; death results from respiratory
insufficiency, cerebral hemorrhage secondary
to undermineralization of the skull, or cervical spinal
cord compression due to abnormalities of the base of
the skull.
• Type 3 01: Inheritance can be either autosomal dominant
or autosomal recessive . Clinical differentiation
from type 2 is based on the longer survival for type 3
patients.
• Type 4 01: This category further subdivides into two
subtypes, A and B . In both types, inheritance is autosomal
dominant. Subtype A has no dentinogenesis
imperfecta or blue sclerae and infrequent fractures.
Subtype B may be relatively indistinguishable from
type 3 due to a very high frequency of fractures.

Front 217

A 2-month-old boy with wheezing.

Back 217

Lymphangioma/hemangioma: These lesions are cystic
masses with a variable amount of solid tissue. Most
of intrathoracic lesions extend downward from the
neck. These diagnoses call1iot be excluded on the basis
of the images presented.
• Teratoma: These lesions are also cystic mediastinal
masses (with occasional calcification and variable solid
components), usually located in the anterior mediastinum.
This diagnosis is a likely consideration based
on the findings presented.
• Other germ cell tumors: Such lesions are rare in
infancy.
• Bronchogenic cyst: This entity is an wilikely diagnosis.
When situated in the mediastinum, bronchogenic
cysts are typically subcarinal in location rather than in
the anterior mediastinum.
• Esophageal duplication: This diagnosis is unlikely
because esophageal duplications are located in the
middle, not anterior, mediastinum.
• Lymphoma: This diagnosis is wilikely because lymphomas
are usually solid masses that are found in older
children and adolescents.
• Normal thymus: Normal thymic tissue can have an
asymmetric anterior mediastinal distribution, but the
normal thymus does not narrow the airway and is not
cystic.
• Thymic cyst: This diagnosis is unlikely because these
lesions are rare in infancy.
• Abscess/hematoma: These diagnoses is unlikely
because there is no history of infection, instrumentation,
trauma, or a bleeding disorder.
• Aneurysm/dilated ascending aorta: These diagnoses
would be unlikely based on the young age of the
patient. Furthermore, dense contrast enhancement of
the lesion would be expected if the mass were vascular.
+DIAGNOSIS: Cystic teratoma (mature).
+ KEY FACTS
CLINICAL
• Respiratory distress is a common clinical presentation
for neonatal mediastinal masses.
• Teratomas contain tissues derived from all three embryonic
cell layers: mesoderm, endoderm, and ectoderm.
449
• The mediastinum is the third most common location,
exceeded only by the pelvis ( ovarian/sacrococcygeal )
and CNS.
• Most anterior mediastinal teratomas have mature histologic
features. Teratomas with mature histologic features
are almost always benign. However, teratomas
with immature histologic features can be either benign
or malignant.
• Cystic teratomas are more likely benign, whereas solid
teratomas are more likely malignant.
• Malignant teratomas often have some histologic components
of other germ cell tumors, e.g., yolk sac
tumors and embryonal cell tumors.
• Exact diagnosis of a cystic mediastinal mass using
imaging methods alone can be difficult. Because of this
fact and because these lesions can produce life-threatening
symptoms and signs (e.g., airway compromise ),
virtually all masses are removed, if possible.

Front 218

A 6-month-old boy with renal insufficiency and failure to thrive.

Back 218

Neurogenic bladder: Bladder wall irregularity, thickened
muscle bundles, and vertical orientation of the
bladder suggest the presence of neurogenic bladder
dysfunction . However, urethral abnormalities are not
present with an isolated neurogenic bladder.
• Megaureter: The dilated, tortuous left ureter seen in
this case is similar to primary megaureter. However,
the distal ureter in this case does not taper as usually
seen in mega ureter. Furthermore, the bladder and urethral
abnormalities are not explained by this diagnosis.
• Urethral polyp: Filling defects in the urethra may
cause obstructive symptoms and poor urinary stream,
as in this case. Benign fibrovascular polyps typically
arise in the region of the verumontanum and prolapse
into the prostatic urethra on voiding images. The filling
defect in the case illustrated, however, is more
web-like and nonmobile.
• Urethral stricture: Focal narrowing of the urethra is
usually due to previous trauma, scar/inflammatory tissue,
or surgery. The retrograde urethrogram ( Figure
8-20D) shows that the urethra is actually normal in
caliber but contains a filling defect that impedes antegrade
urine flow.
• Posterior urethral valves: This entity is the best diagnosis,
given the posterior urethral filling defect and
associated bladder and upper urinary tract findings.
DIAGNOSIS: Posterior urethral valves.
+ KEY FACTS
CLINICAL
• Posterior urethral valves are the most common cause
of urethral obstruction in boys. Early diagnosis and
treatment (now sometimes in utero) can help to preserve
renal function.
• Boys with urine ascites, hydronephrosis, hydroureter,
or poor urinary stream should be evaluated with voiding
cystourethrography (VCUG) using steep oblique
views of the urethra during voiding to detect the presence
of urethral valves.
• Vesicoureteral reflux is common in boys with posterior
urethral valves and, when unilateral, may be protective
for the contralateral kidney.
• The valve tissue results from abnormal fusion of remnants
of the mesonephric duct. In normal circumstances,
fusion of the remnants of the mesonephric
duct forms the plicae collicularis or mucosal folds in
the urethra. However, if this tissue nlses in the midline,
a thin flap is formed that acts like a windsock or
diaphragm, impeding urine flow.
451
• The valve tissue is typically very thin and transparent at
cystoscopy and may be pushed aside by the cystoscope
if not carefully sought. Thereafter, cytoscopic resection/
ablation is performed.
• Prognosis is generally good if renal function has not
been compromised by prolonged high-grade obstruction,
back pressure, and secondary dysplasia.
• A classification of posterior urethral valves (into types
1 , 2, and 3 depending on the configuration of the
obstructing valve ) has been proposed but is not clinically
useful.

Front 219

A 9-month-old female who presented in the neonatal period with profound
cyanosis.

Back 219

Isolated pulmonic valve stenosis: A decrease in pulmonary
blood flow would not be expected in the setting
of isolated pulmonic valve stenosis (i.e., in the
absence of an intracardiac shw1t). In this entity, the
entirety of blood flow must pass through the lungs.
Therefore, the typical finding is a dilated main pulmonary
artery with normal flow.
• Tetralogy of Fallot (TOF): The combination of a
large subaortic ventricular septal defect (VSD), right
ventricular hypertrophy, and small pulmonary arteries
is typical of this diagnosis. These findings are all present
in the case illustrated, making this the most likely
diagnosis. The majority of these patients have a left
aortic arch, although 25% have a right aortic arch (see
Case 2 1 in Chapter 7 ) .
• Pulmonary valve atresia with intact ventricular septum:
The presence of cardiomegaly and diminished
pulmonary blood flow on the radiographs raises tllis as
a possible diagnosis. However, the presence of a large
VSD on the MRI excludes this diagnosis.
• Ebstein's anomaly: Patients with Ebstein's anomaly
usually present with cyanosis in the neonatal period
and have marked right-sided cardiac enlargement
(including both the right atrium and right venu·icle )
and diminished pulmonary blood flow (as a result of
severe tricuspid regurgitation and right-to-left shunting
across the atrial septum). This diagnosis is wilikely
for two reasons: ( 1 ) cardiac size is usually ( but not
invariably) much larger than shown in Figure 8-2 1 Ain
particular, the right heart size is increased in
Ebstein's anomaly but not in the case shown above;
and ( 2 ) the MRIs in this case show an aorta overriding
a VSD, not a feature of Ebstein's anomaly.
• Tricuspid atresia: These patients can present with cardiomegaly
and diminished pulmonary blood flow.
However, the presence of a normal, thick-walled right
ventricular chamber on the MR examination in the
case shown makes this an unlikely diagnosis.
DIAGNOSIS: Tetralogy of Fallot with diminutive
pulmonary arteries following central shunt.
KEY FACTS
CLINICAL
• The finding of cyanosis with normal or dinlinished
pulmonary vascularity is usually caused by a combina-
453
tion of a ventricular communication and pulmonic
stenosis. The exceptions to this rule are Ebstein's
anomaly of the tricuspid valve and pulmonary atresia.
• TOF can be associated with pulmonic stenosis at any
of four levels: the infundibulun1 ( most common), the
pulmonic valve, tl1e pulmonary trunk, or the pulmonary
artery branches.
• If pulmonary atresia is present, the entire pulmonary
blood flow is through collateral (bronchial ) vessels that
reach the pulmonary vasculature from the descending
tl10racic aorta.
• TOF is the most common malformation among cyanotic
adults with congenital heart disease.

Front 220

A 2-month-old former premature infant who has spent her entire life in the
neonatal intensive care unit.

Back 220

Rickets: The radiographic findings in this case-i.e.,
metaphyseal flaring and irregularity and insufficiency
fractures-are typical of rickets. In premature infants,
dietary vitamin D deficiency is the usual etiology.
• Hypophosphatasia: This entity, due to deficient activity
of alkaline phosphatase, should be considered
because the radiographic changes may be virtually
indistinguishable from rickets. The distinction is made
on the basis of findings of premature cranial synostosis
and increased excretion of urinary phosphoethanolamine
in hypophosphatasia.
• Child abuse: As with rickets, multiple fractures are typically
seen. In a child of this age, the fractures may well
be diaphyseal. However, mineralization in child abuse will typically be normal (unlike rickets), without metaphyseal
flaring. Furthermore, the irregularity of the
metaphyses seen in rickets will not be seen in child abuse.
• Osteogenesis imperfecta (01): Like rickets, undermineralization
and multiple fractures are seen (see
Case 1 8 ) . However, rickets is not associated with the
gracile bones commonly seen in 01. In fact, it is the
absence of this characteristic finding that makes 01 an
unlikely diagnosis in the case shown.
+ DIAGNOSIS: Rickets.
KEY FACTS
CLINICAL
• Rickets usually presents by 3 to 6 months of age and is
almost always diagnosed by age 2 years.
• Clinical manifestations include weakness, tetany,
kyphoscoliosis, and craniotabes.
• Nutritional causes can be classified as either secondary
to decreased vitamin D synthesis ( as can occur in
absence of exposure to sunlight, particularly with dark
skin) or due to dietary vitamin D deficiency. Premature
infants are especially susceptible to rickets from the latter
cause. In these children, a diagnosis can be confirmed
by finding serum alkaline phosphatase levels
> 1 0 times the normal value in adults.
• A variety of intestinal disorders can cause malabsorption
of vitamin D and subsequent rickets: pancreatic
insufficiency, as might be seen with cystic fibrosis; biliary
disease (e.g., biliary atresia); and small-bowel disease,
including regional enteritis or short-gut syndrome
following resection of diseased bowel.
455
• A wide spectrum of renal disorders, either glomerular
or tubular in nature, can cause rickets. Among the latter
is vitamin D-resistant rickets.
• Increased requirement for vitamin D may be responsible
for rickets. It may be inherited or acquired (e.g.,
anticonvulsant therapy, especially phenytoin ) .
• Rarely, tumors (e.g., giant cell tumor, fibroma, hemangiopericytoma)
can cause rickets.

Front 221

A 1 2-year-old boy with a cardiac murmur.

Back 221

Anterior mediastinal mass: An anterior mediastinal
mass could be suspected because of the frontal chest
radiograph findings. However, the lateral radiograph
shows that not all of the abnormal density is in the
anterior mediastinum; some is also posterior, near the
location of the left ventricle. Furthermore, the clinical
history (a cardiac murmur) would not be accounted
for by the presence of an anterior mediastinal mass.
Finally, the MR study shows definitively that a structural
cardiovascular lesion is present.
• Ascending aortic aneurysm: This diagnosis best
accounts for the imaging findings. The MR findings
explain the unusual appearance of the chest radiograph.
The anterior soft tissue is the ascending aortic
aneurysm. The left ventricle is enlarged because of aortic
regurgitation (not shown) .
• Aortic stenosis: The enlargement of the ascending
aorta in this case could potentially be due to the jet
effect of aortic stenosis. However, at a point at which
the aorta was enlarged to the degree shown in the illustrated
case, clinical symptoms and signs (e.g., dyspnea,
exertional chest pain, syncope, or an apical systolic ejection
murmur) would be expected to be quite evident.
+ DIAGNOSIS: Ascending aortic aneurysm in
Marfan's syndrome.
+ KEY FACTS
CLINICAL
• Aneurysms of the ascending aorta are rare in children
but are much more common in adults (in whom the
most common etiology is atherosclerotic disease) .
• Ascending aortic aneurysms i n children are usually due
to genetic disease ( Marfan's syndrome, cutis laxa,
pseudoxanthoma elasticum, Ehlers-Danlos syndrome,
homocystinuria, osteogenesis imperfecta, Noonan's
syndrome, or Turner's syndrome).
• In Marfan's syndrome, an abnormality of the elastic
media is present ( "cystic medial necrosis" is a term that
has been used, although it is a misnomer because
necrosis is not present). Other major cardiac anomalies
in Marfan's syndrome are aortic and mitral insufficiency,
as well as dissection of the aneurysm.
• Ehlers-Danlos syndrome represents a group of related
collagen disorders. Hyperelasticity and joint laxity are
typical clinical features.
• In homocystinuria, mental retardation is present,
unlike in the case illustrated.
457
• 01 type 1 is associated with aortic group dilatation. A
clinical history of fractures or blue sclera ( not present in
the case illustrated) is typically present.
• Repair of the ascending aorta usually is performed for
an aneurysm of 6.0 cm in the adolescent or adult.
Aortic surgery or aortic valve or mitral valve replacement
is rarely necessary before adolescence in Marfan's
syndrome.
RADIOLOGIC
• Although plain films are sometimes the initial imaging
technique for detection of ascending aortic aneurysm,
they have little value in the follow-up of these patients.
• Echocardiography is a helpful noninvasive tool for
determining the dimensions of the ascending aortic
aneurysm, the presence of valvular regurgitation, and
evaluating left ventricular function.
• MRl is recommended in situations where the acoustic
window is limited ( including Marfan's syndrome,
where pectus deformity may limit evaluation) and in
patients with known dilation of the ascending aorta
and acute chest pain ( in whom aortic dissection is
suspected) .

Front 222

HISTORY
A 7-year-old white boy with right hip pain and a limp with no clinical or laboratory
fmdings suggesting further infection.

Back 222

Differential diagnosis for avascular necrosis of the hip in a
child includes:
• Legg-Calve-Perthes disease (Legg-Perthes disease):
This diagnosis is possible given the patient's age and
findings of avascular necrosis.
• Sickle cell anemia: This diagnosis is not likely because
the child is white. Other bony changes associated with
sickle cell hemoglobinopathies including sclerosis,
"bone-within-bone" appearance in the femurs, and
periosteal reaction ( from acute infarction or, less commonly,
osteomyelitis) are not present.
• Trauma: The absence of a history of trauma makes
this an unlikely diagnosis.
• Osteomyelitis: Osteomyelitis can cause changes that
mimic avascular necrosis, but clinical and laboratory
features consistent with infection are usually present.
Osteomyelitis can be distinguished from avascular
necrosis by a bone scan that shows increased radiotracer
activity in all phases of a three-phase scan ( wuess
there is loss of vascular supply due to mechanical factors
such as infectious synovitis) .
• Gaucher's disease: Osteonecrosis can occur in
Gaucher's disease, but other stigmata of Gaucher's disease,
including expanded medullary cavities with a thin
cortex, osteopenia, and absence of normal metaphyseal
widening, are not present in the cases shown.
• Corticosteroid use: Corticosteroid use can cause avascular
necrosis, but such history is absent here.
Diagnostic considerations for fragmented epiphyses include:
• Hypothyroidism: This diagnosis is not likely because
both femoral heads in hypothyroidism are fragmented
at the onset of ossification . The left femoral head
shown in Figure 8 -24C is not fragmented.
• Multiple epiphyseal dysplasia: With age, the epiphyseal
fragments often coalesce and resemble the coxa
magna appearance seen in Figure 8-24C. However,
this diagnosis is not likely as it is also usually bilateral
and symmetric.
• Legg-Calve-Perthes disease: In advanced stages of
this disease, fragmented epiphyses can be seen. Unlike
the two entities previously mentioned, findings are
usually unilateral, making it a realistic diagnostic
possibility. Furthermore, it is the only entity on both
differential diagnosis lists (i.e., as a cause of both fragmented
epiphyses and avascular necrosis of the hip),
making it the most likely diagnosis.
+ DIAGNOSIS: Legg-Calve-Perthes (or LeggPerthes)
disease.
+ KEY FACTS
CLINICAL
• Legg-Perthes is most conunon in white boys. The age
range is 3 to 12 years, but most cases occur between the
ages of 5 and 8 years. The male-to-female ratio is 4 to 1 .
459
• Bilateral abnormalities are present in about 1 0% of
cases. Symptoms and signs include a limp, pain, thigh
and buttock atrophy, and limited internal rotation.
Pain may be centered about either or both the hip and
groin or referred to the knee.
• Older age at onset of symptoms and female gender are
associated with a worse prognosis.
• Most children with Legg-Perthes remain symptom free
after the acute event for decades even though radiographic
changes including coxa magna and flattening
of the femoral head persist.
RADIOLOGIC
• The plain film findings in the first few weeks after
symptom onset may be widening of the joint space
medially and lateral displacement of the femoral head,
reflective of edema of either or both the acetabular
fossa tissues, and a small joint effusion.
• Several pathophysiologic explanations have been
invoked to explain the increased density of the femoral
head. For example, sclerosis may be due to a combination
of decreased demineralization (due to decreased
blood supply) and increased new bone formation (during
a stage of revascularization) . Alternatively, the
increased density may be only apparent, compared to
disease-related osteopenia in the femoral neck.

Front 223

A previously healthy 3-year-old boy with 2 days of enuresis, dysuria, and hematuria.

Back 223

Neurogenic bladder: Patients with neurogenic bladder
frequently have bladder wall thickening, heavily
trabeculated bladder muscle, and debris related to
intermittent catheterization . The case illustrated above
had no history of bladder dysfunction. The acute onset
of symptoms is also not consistent with tl1e history of
neurogenic bladder.
• Augmented bladder: Cystoplasty, using a part of the
gastrointestinal tract, is a common surgical method
used to augment bladder capacity that results in an
irregularly shaped outer contour of tl1e bladder. The
bladder in tlus case has a smooth outer contour (even
mough the inner contour is undulating), inconsistent
with tl1e diagnosis of augmented bladder.
• Rhabdomyosarcoma: This diagnosis is a consideration
because the bladder wall is tl1ickened. Bladder sarcoma
typically appears as a focal mural mass or region of
tl1ickening and can project into the bladder lumen as a
polypoid mass ( botryiodes configuration). If the mass
ulcerates or hemorrhages, echogenic material may be
seen in the urine at sonography. However, diffuse
bladder wall involvement is W1Common in bladder sarcoma,
as is the acute onset of symptoms.
• Eosinophilic cystitis: This uncommon entity could
cause a similar sonographic appearance or produce
polypoid lesions projecting into me bladder lumen.
Peripheral eosinophilia ( not present in tl1is case) and a
negative urine culture are diagnostic.
• Hemorrhagic cystitis: The signs, symptoms, and
sonogram are consistent wim tl1is general diagnosis,
which has a number of different causes. There is no
history of recurrent skin or pulmonary infection to
support a diagnosis of cystitis of chronic granulomatous
disease. A I1istory of chemotherapy treatments,
which would raise the diagnosis of cytoxan-related cystitis,
is not present. No bleeding disorder, trauma, or
radiation therapy that might serve as a cause of hemorrhage
is reported in tl1is patient. By exclusion, merefore,
infection is the most likely cause in tl1is case
based on the clinical information.
• DIAGNOSIS: Hemorrhagic viral cystitis.
+ KEY FACTS
CLINICAL
• Acute cystitis with hemorrhage is a fairly common
entity in childhood, usually discovered during evaluation
for acute onset of gross hematuria, dysuria, frequency,
and urgency. Suprapubic pain, fever, and
enuresis are less common complaints. In the absence
of bacteruria, adenovirus ( types 1 1 and 2 1 ) is the most
common causative agent. Varicella and cytomegalovirus
cystitis are less common forms.
461
• An antecedent upper respiratory tract infection may be
associated in the minority of cases.
• Virus can be isolated from urine specimens. Alternatively,
the presence of virus is inferred from the
acute and convalescent serum neutralizing antibody
titers. The diagnosis is often presumptive and made on
clinical grounds.
• The illness is usually self-linuted and lasts a few days to
a few weeks. Treatment is supportive, with emphasis
on good hydration.
• Otl1er genitourinary tract anomalies and neoplasms
must be excluded when symptoms persist.
• Unlike bacterial cystitis, which is more common in
females and thought to result from retrograde
transuretlrral spread, viral cystitis has no gender
predilection and is likely caused by hematogenous
spread.

Front 224

A 4-week-old, 32-week-gestation neonate with feeding intolerance and
guaiac-positive stools.

Back 224

Malrotation with midgut volvulus: This entity is seen
in the neonatal period and can cause volvulus, pneumatosis,
and perforation. A history of vomiting (typically
bilious) is nearly always present, unlike the case shown.
• Meconium ileus: This entity is almost always seen in
cystic fibrosis; however, pneumatosis is infrequent, and
a soap-bubble appearance of the intraluminal contents
in the right lower quadrant due to inspissated meconium
is usually present.
• Malrotation with Ladd's bands: This entity can
cause bowel obstruction, ischemia, pneumatosis, and
perforation, but it does not usually present in the
neonatal period or with distal obstruction.
• Bowel atresia: Atresia also presents in the immediate
neonatal period. However, bowel dilation is typically
much more severe than in the case illustrated. Air
would not be expected in the rectum.
• Meconium plug syndrome: This entity is rarely seen
in preterm children. Pneumatosis is not typical .
• Small left colon: This entity usually causes obstruction
in the newborn period but is an unlikely diagnosis
because pneumatosis is not typically present.
• Hirschsprung's disease: This may be considered because
it typically presents in the neonatal period, with failure to
pass stool in the first 24- to 36-hour period. However,
pneumatosis is rare in the absence of enterocolitis, a complication
seen beginning several weeks after birth.
Other disorders of peristalsis include :
• Sepsis/hypoxemia/hypotension: These entities can
cause ileus, bowel wall ischemia, and pneumatosis, but
the case presented did not have features indicative of
these entities--e.g., cardiovascular collapse or history
of respiratory difficulty or infection.
• Necrotizing enterocolitis (NEC): This entity is the
best diagnosis, based on the history of prematurity,
feeding intolerance, guaiac-positive stools, and the
plain-film findings of pneumatosis, portal venous gas,
and bowel perforation.
+ DIAGNOSIS: Necrotizing enterocolitis.
+ KEY FACTS
CLINICAL
• NEC is a result of intestinal mucosal injury with breakdown
of the mucosal protective barrier, allowing bacterial
proliferation and mural invasion. Abnormal
peristalsis is also frequently a contributing factor.
• Approximately 80% of NEC cases occur in premature
infants, usually between 3 and 6 days of life during initiation
(or advancement) of feeds.
• NEC affects 1 % to 5% of all neonates admitted to tlle
intensive care nursery, and about 1 2 % of premature
infants weighing < 1 500 g.
• NEC is associated with hypoxia, stress, ischemia, and
infection. Term infants with NEC usually have a severe
463
underlying disease--e.g., mechanical bowel obstruction
or congenital heart disease (leading to embolus) or
indwelling catheters ( e.g., umbilical vascular catheters ) .
• Clinical features involve the cardiorespiratory system (e.g.,
apnea, tachypnea/tachycardia, hypotension, lethargy),
gastrointestinal system (gastric retention witll feeding
residuals, vomiting, abdominal distention, bloody stools),
and peritonitis in cases of bowel perforation.
• Clinical indications for surgery ( consisting of resection
of necrotic bowel ) include intraperitoneal free air, peritonitis,
shock, persistent metabolic acidosis, and disseminated
intravascular coagulation.
• Patients with NEC are at increased long-term risk of
bowel strictures and adhesions ( usually at the splenic flexure)
and short-gut syndrome with severe malabsorption.

Front 225

A 36-hour-old neonate with failure to pass meconium. Visual inspection of the
anus revealed no abnormalities.

Back 225

Meconium plug syndrome: Contrast material should
clearly outline extensive tubular filling defects ( meconium
plugs) in meconium plug syndrome, which is not
seen in the case illustrated.
• Small left colon syndrome: This entity is a consideration
because of the obstruction and a relatively small
left colon. A history of maternal diabetes would
increase the likelihood of small left colon syndrome .
• Anal atresia: Absence of an anus would be expected
on physical examination. Therefore, this is an incorrect
diagnosis in the cases shown.
• Colon atresia: This very rare entity is diagnosed by a
contrast enema showing atresia, not seen in the case
shown.
• Meconium ileus: The history given for tlus patient
raises the possibility of meconium ileus, but bilious
vomiting is often present. Barium enema often shows a
small, unused colon, lllilike that in the cases presented
here.
• neal atresia: The history and radiographic evidence of
distal obstruction make tllis a possible diagnosis.
However, bilious vomiting is typically present, which is
not seen in the case illustrated.
• Hirschsprung's disease (aganglionosis): This diagnosis
is a reasonable consideration given the history of
failure to pass mecoluum and colonic obstruction.
Although Hirschsprung's disease usually involves only
a short segment of colon, a rare form of the disease
can involve a long segment. The radiographic findings
of rectosigmoid spasm and narrowing ( Figure 8-27C)
is seen in short-segment disease.
• DIAGNOSIS: Hirschsprung's disease.
+ KEY FACTS
CLINICAL
• Hirschsprung's disease is the most common cause of
bowel obstruction in the neonate, usually presenting
with obstruction or intermittent diarrhea and constipation.
• Symptoms usually date from birth, with a failure to
pass meconium during the first 24 hours of life and
often bilious vomiting.
• The etiology of Hirschsprung's disease is thought to
be an arrest of the craniocaudal migration of neuroblasts,
producing an absence of ganglion cells in myenteric
and submucosal plexus. This results in a
hypertonic state with failure of relaxation of the aganglionic
segment.
• Patients are usually term infants. An association with
Down's syndrome (trisomy 2 1 ) has been described.
• The diagnosis of Hirschsprung's disease is important
to establish quickly. Complications include pneumatosis,
perforation, and enterocolitis ( presumably due to
ischemia of the bowel caused by stasis and distention
of colon proximal to the obstruction) .
• A 50% mortality rate b y 1 year o f age i s reported i n
untreated cases.
465
• Four pathologic types have been described: ultrashort-
segment disease ( however, the true existence of
this entity is in question), short-segment disease (80%),
long-segment disease ( 1 5%), and total colonic
Hirschsprung's disease ( 5% ) .
• Contemporary diagnosis in the neonate and young
child is by suction biopsy, which has replaced barium
enema as the principal means of diagnosis. Suction
biopsy is less sensitive in older children and therefore
more reliance is placed on contrast enema evaluation
in these children.

Front 226

A I -month-old infant who presented at birth with pneumonia but has remained
tachypneic after resolution of the infection.

Back 226

Pulmonary sling (aberrant origin of left pulmonary
artery from the right pulmonary artery): The finding
of an aberrant vessel arising from the left pulmonary
artery and coursing posterior to the trachea is
characteristic of this diagnosis. Either air trapping,
atelectasis, or both can be present. Atelectasis was an
intermittent finding in the case illustrated. This is the
correct diagnosis.
• Vascular rings causing airway compression:
(a) Double aorta arch or circumflex aorta: This lesion
can cause stridor, but unlike the case illustrated, aeration
would be expected to be symmetric. Furthermore, a
right arch is not seen on the plain film in the case illustrated.
(b) Right arch with anomalous left subclavian
artery and liganlentum arteriosum: This anomaly should
be considered because it can cause respiratory symptoms,
as in the case illustrated. However, the MRI study
shows that it is the left pulmonary artery, and not the
subclavian artery, that has an anomalous origin. (c) Left
aortic arch with aberrant right subclavian artery: The
same reasoning as for (b) applies to this diagnosis.
• Tracheal compression by the brachiocephalic
artery: This vascular anomaly can cause stridor, usually
evident by 6 months of age. However, in this anomaly,
the compression is by a vessel that is anterior to the
trachea (unlike the case illustrated) and the pulmonary
arteries are normal. The affected infant may outgrow
the airway compromise, but occasionally an arteriopexy
is needed to relieve significant compromise that
produces clinical symptoms.
• Other anatomic causes: The trachea can be compressed
by enlargement or midline position of the
aorta, pulmonary arteries, or left atrium. The descending
aorta is normally positioned in the present case.
Furthermore, no enlargement of cardiovascular structures
is seen in this case. None of these causes are
likely explanations for the findings in the case shown.
DIAGNOSIS: Aberrant left pulmonary artery
(pulmonary artery sling).
+ KEY FACTS
CLINICAL
• Vascular "rings" and "slings" often produce respiratory
symptoms, chiefly stridor, in infants and small children
(occasionally as apnea during feeding). Dysphagia is
467
more common in older children and adults with these
vascular anomalies.
• Bronchoscopy performed to evaluate stridor can provide
the first evidence of a vascular anomaly by showing
an extrinsic, pulsatile mass compressing the trachea.
• Rings and slings are often associated with tracheomalacia.
The infant may outgrow the tracheal deficiency
after vascular repair, but airway reconstruction may be
necessary if compromise is significant.
• A pulmonary sLing is one of the rarer of the vascular
anomalies with airway compromise. There can be a
spectrum of associated tracheal anomalies, including
tracheomalacia, complete cartilaginous rings, stenosis,
aberrant origins of bronchi, and atresias. The surgeon
performing the vascular repair must take into consideration
the potential need for airway reconstruction.
• Pulmonary sling is occasionally associated with structural
cardiac disease, usually tetralogy of Fallot.