Differential Chest

Front 1

Seemingly normal CXR:

Back 1

tracheomegaly, dilated esophagus, PTX, lobar collapse

Front 2

Interstitial (general/perihilar) on CXR:

Back 2

interstitial pulmonary edema, lymphangitic spread of CA (colon, lung, breast, gastric), infectious (viral/Mycoplasma, miliary TB, fungal, PCP)…

Front 3

Apical Cap

Back 3

(if smooth, think extrapleural): subpleural fat extending from mediastinal lipomatosis (smooth), lymphoma/infection extending from the neck or mediastinum (smooth), extrapleural hematoma (smooth), nonspecific apical/subpleural scarring (not smooth), superior sulcus tumor, radiation fibrosis

Front 4

Bronchiectasis (irreversible dilitation of the bronchi - may be cylindrical, varicoid, or cystic ):

Back 4

postinfectious (most common), congenital (CF, Kartageners, William Campbell, Mounier-Kuhn); ABPA (usually central and varicoid bronchiectasis – not seen until finger and glove clear; classic additional findings are mucoid impaction, patchy migratory atelectasis and consolidation)

Front 5

Crazy Paving (smoothly thickened septal lines superimposed on ground glass opacities):

Back 5

PAP, edema, infection…esp viral or PCP (look for cysts)

Front 6

Collapse of entire lung:

Back 6

mucous plug, aspirated FB, malpositioned ETT, obstructing neoplasm (bronchogenic CA, carcinoid, mets)

Front 7

Mosaic pattern

Back 7

Air trapping 2o small airways disease (get expiration view): BO, URI with bronchiolitis, asthma
Decreased perfusion 2o small vessels disease: vasculitis, microemboli
Imflammatory: infection, hypersensitivity pneumonitis

Front 8

Miliary nodules (look for superior medistinal mass – thyroid):

Back 8

(3-5mm) Infection (TB, fungi – disseminated histo or blasto [may or may not be immunocompromised], varicella) , mets (melanoma, RCC, chorioCA, thyroid), silicosis, healed varicella, Langerhans cell histiocytosis

Front 9

Multiple cavitary lesions:

Back 9

Septic emboli (Staph secondary to IVDA or indwelling line, Apergillus/Mucor in immunocompromised), mets (usually SCC), Wegener’s (appears angiocentric!)

Front 10

Solitary Cavity:

Back 10

TB, fungal (cocci…which is usually thin grapeskin walled, histo, blasto) pyogenic abscess (Staph, Klebsiella, E coli, Pseudomonas, anaerobes), bronchogenic CA (usu sq cell), Nocardia, secondary Aspergillus infection of cavity, septic emboli (Staph aureus), mets (usu sq cell), lymphoma (Hodgkin’s), rheumatoid nodule, Wegener’s, large hiatal hernia, silicosis, lymphomatoid granulomatosis, Echinococcus (also thin wall)

Front 11

Smooth or nodular centrilobular and interlobular septal thickening on HRCT (with preservation of architecture):

Back 11

Lymphangitic spread of CA (colon, lung, breast, gastric), lymphoma, sarcoidosis, and Kaposi’s

Front 12

Solitary pulmonary nodule:

Back 12

granuloma (TB, fungus ESPECIALLY HISTO…fungal nodules account for 30% solitary pulmonary nodules per Galvin), hamartoma, lung CA, carcinoid, met, lymphoma, abscess, bronchogenic cyst, AVM, and if immunocompromised: Nocordia, Aspergillus, and PTLD…

Front 13

Large thoracic mass:

Back 13

tumor (bronchogenic CA, lymphoma), mets, infection (abscess, round PNA), rounded atelectasis, sequestration, hematoma; extrapulmonary – fibrous tumor of pleura, loculated effusion , chest wall mass, mediastinal mass, AAA

Front 14

Tubular opacity on CXR or CT:

Back 14

Mucoid impaction (ABPA, CF, obstructed bronchus distal to mass, congenital bronchial atresia) versus vascular malformation

Front 15

HIV with lung nodule:

Back 15

: fungal, mycobacterial (TB), septic infarct, Kaposi’s, lymphoma

Front 16

Post-transplant lung nodule(s):

Back 16

infection – Aspergillus, Nocardia, CMV (usually no LAD with infections) versus PTLD (4-6 mos post transplant with assd LAD)

Front 17

Post-lung transplant complications:

Back 17

reperfusion edema (fist 1-5 days), acute rejection (1st 3 mos), infection (1st month = bacterial, after 1st month – CMV)

Front 18

Endobronchial spread of infection (tree-and-bud):

Back 18

Bacterial: TB, MAC, Staph, H. flu; Fungal: Apergillus; Viral: CMV, RSV

Front 19

Unilateral absence of perfusion on Tc99-MAA scan:

Back 19

hilar/mediastinal mass, ascending aortic aneurysm, hypoplastic pulmonary artery, s/p pneumonectomy, large PE

Front 20

Interstitial upper zone:

Back 20

CASSETP – CF (not an interstitial disease), AS, sarcoid, silicosis, EG, TB, PCP, chronic hypersensitivity pneumonitis, radiation fibrosis, chronic fungal infection

Front 21

Interstitial lower zone:

Back 21

BADARDS – bronchiectasis (not an interstitial disease), asbestosis, drugs (amiodarone, bleomycin, MTX), aspiration (chronic), RA, DIP/UIP, SLE/scleroderma, neurofibromatosis

Front 22

Peripheral consolidation:

Back 22

BOOP/COP (cryptogenic organizing pneumonia – peripheral AND peribronchovascular consolidation), eosinophilic PNA (often biapical/biaxillary distribution), pulmonary infarcts, vasculitis

Front 23

Cardiophrenic angle mass:

Back 23

prominent pericardial fat pad (most common), pericardial cyst, Morgagni hernia, epicardial lymph nodes (common site of recurrence for Hodgkins), thymic mass

Front 24

Mediastinal widening (look at trachea):

Back 24

tortuous brachiocephalic vessels or aorta, fatty deposition (mediastinal lipomatosis), mediastinal hemorrhage, malignant adenopathy, lymphoma, enlarged thyroid, mediastinitis, lung CA, thymic lesion, teratoma

Front 25

Mediastinal Adenopathy:

Back 25

General – metastatic LAD, lymphoma, TB, fungal infection (especially Histo which classically mimicks sarcoidosis), sarcoidosis
Low attenuation – TB or fungal infection esp in AIDS, necrotic mets, lymphoma, seminoma;
Enhancing/Vascular – Castleman’s, vascular mets (RCC, thyroid, melanoma, carcinoid, small cell, KS, chorioCA);
Calcified – TB, fungal, sarcoid, silicosis, lymphoma post radiation, disseminated PCP (immunocompromised)
Intrathoracic nodal mets – GU (renal, testicular), head and neck (skin, larynx, thyroid), breast, melanoma, KS

Front 26

Peribronchovascular/axial nodules:

Back 26

sarcoid, lymphangitic carcinomatosis, KS, lymphoma, bronchiolitis obliterans.

Front 27

Reterosternal nodular opacity on lateral CXR:

Back 27

metastatic LN’s (breast CA or lymphoma), enlarged internal mammary vessels secondary to aortic coarctation (associated with rib notching) or SVC syndrome (associated with right suprahilar mass)

Front 28

Tracheobronchomalacia

Back 28

(excessive airway collapsibility – must be diagnosed by comparing inspiration and expiration films – >50% narrowing is abnl): prolonged ETT, COPD, congenital cartilaginous deficiency, relapsing polychondritis, Wegener’s, amyloidosis, sarcoidosis, TB, tracheopathia osteochondroplastica (submucosal cartilaginous and osseous nodules of various sizes that cause a narrowing of the upper respiratory tract)

Front 29

Tracheal lumen:

Back 29

Increased (>2.5 cm AP at 2 cm above arch) – congenital tracheobronchomegaly (mounier Kuhn), pulmonary fibrosis, tracheomalacia;
Decreased – saber-sheath (COPD), tracheomalacia, relapsing polychondritis, sarcoid, amyloid, Wegener’s, TB and fungal stenosis, tracheopathia osteochondroplastica

Front 30

Tracheal masses (intraluminal):

Back 30

#1 papilloma, #2 amyloidosis (low T1 and T2), TB, SSC, adenoid cystic CA, mets (any vascular met)

Front 31

Lobar Pneumonia

Back 31

(initial site of inflammation is alveolus, secondary pulmonary lobule completely opacified; spread occurs at intra-alveolar level hence may not conform to segmental anatomy): Strep pneumonia (#1), Klebsiella (#2 – lobar expansion aka Friedlanders pneumonia), Haemophilus

Front 32

Lobar pneumonia with necrosis/cavitation:

Back 32

Strep pneumonia (#1), Klebsiella (#2)

Front 33

“atypical pneumonia”

Back 33

= bronchiolitis ± bronchopneumonia; causes include Mycoplasma pneumonia (#1), viral infection (influenza, adenovirus), Legionella (#2)

Front 34

Bronchopneumonia

Back 34

(initial site of inflammation is bronchiole, secondary pulmonary lobule incompletely opacified): Staph, gram negatives, anaerobes, mycoplasma, legionella

Front 35

Nodular or masslike infectious consolidation:

Back 35

round pneumonia (Strep pneumonia), TB, fungus (blasto likes to do this), actinomycosis (likes to cross pleura into ribs and chest wall), nocardia (will also cross pleura into chest wall!)

Front 36

Complications of pneumonia

Back 36

necrosis secondary to vascular thrombosis, bronchopleural fistula, lung abscess, pneumatocele (ball valve effect, assocated with Staph in pediatric patients), bronchiectasis

Front 37

PAH

Back 37

systolic >30mmHg, primary (young female), secondary (chronic lung dz, chronic PE, L to R shunts, mitral stenosis, LV failure, vasculitis, drugs)

Front 38

PA stenosis

Back 38

congenital pulmonary valve stenosis (enlarged main and left PA with sparing of right PA), “TOF with absent pulmonary valves” (implies a hypoplastic pulmonic annulus and is associatd with TOF), Takayasu, rubella, Williams syndrome;

Front 39

PA dilatation

Back 39

poststenotic jet, Osler-Weber-Rendu;

Front 40

PA Aneurysm

Back 40

Takayasu, Behcets, vasculitis, trauma, infection

Front 41

Aortic aneurysm types:

Back 41

In a true aortic aneurysm, all layers of the aortic wall are intact (usually secondary to atherosclerosis but also seen with Marfans, Ehlers Danlos, syphilis, aortc valve disease). In a false aneurysm there is focal disruption of one or more layers.

Front 42

Partial absence of the pericardium

Back 42

can look just like left atrial appendage enlargement (as seen with rheumatic heart disease). Slight leftward shift of the entire cardiac silhouette (but not trachea) and lung/air extending into AP window favor former dx.

Front 43

Pneumopericardium:

Back 43

barotraumas in childrem, s/p pericardiocentesis or cardiac surgery in adults, penetrating trauma, esophageal fistula (look for fluid level) usually secondary to ulcerating mass

Front 44

Pericardial nodularity + effusion:

Back 44

metastatic disease usually from breast, lung, melanoma, or lymphoma and may be via hematogenous OR lymphatic spread. Effusion may be hemmorhagic.

Front 45

Right Hilar Convex mass on frontal CXR:

Back 45

include Sinus of Valsalva aneurysm with diff dx (as they most frequently arise from the right or the noncoronary sinus)!!! LAD, bronchogenic cyst, PA aneurysm, maybe ascending aortic aneurysm

Front 46

Sinus of Valsalva aneurysm:

Back 46

most frequently arise from the right or the noncoronary sinus; associated with aortic regurg and supracristal VSD.

Front 47

2 types of aortic coarcatation:

Back 47

Congenital = focal and juxtaductal
Acquired = segmental usually from Takayasus or (rarely) giant cell arteritis

Front 48

Types of VSD:

Back 48

Membranous
Muscular
AVSD
Supracristal – between the aortic root and RV outflow tract; associated with aortic insufficiency, sinus of
valsalva aneurysm, and left to right shunt

Front 49

Cardiac viability by MRI:

Back 49

ascertained by delayed post-gad images (7-10 minutes), which demonstrate hyperenhancement in scarred (non-viable) myocardium. Normal myocardium enhances early and washes out. MRI is better than PET in that it allows better spatial resolution so that subendocardial infarct/scar can be distinguished from transmural infarct/scar. Revascularization may be of benefit if the nonviable region is <50% myocardial thickness.

Front 50

Aortic stenosis:

Back 50

Enlargement of the ascending aorta ONLY (jet phenomena), with NORMAL aortic knob and descending aorta. (With aortic regurgitation, see enlargement of all 3). 3 main causes are (1) Congenital aortic stenosis, (2) Degeneration of a bicuspid or tricuspid AV, and (3) Rheumatic heart disease

Front 51

Mitral annulus Ca+:

Back 51

Circular, C or J shaped, atherosclerotic and age-related, assoc with mitral regurgitation

Front 52

Left atrial wall calcifications:

Back 52

Due to chronic outflow obstruction (MV stenosis) and can result in Afib

Front 53

Alveolar OPACITY:

Back 53

pneumonia, aspiration, pulmonary edema, pulmonary hemorrhage; less common – bronchogenic TB, fungus, sarcoid, bronchioloalveolar CA, lymphoma, alveolar proteinosis, aspiration of blood or lipid, leukemia, BOOP, eosinophilic PNA; (blood, pus, water, cells, protein); chronic ASD – bronchioloalveolar CA, lymphoma, alveolar proteinosis, lipoid PNA, alveolar sarcoid, BOOP, eosinophilic PNA

Front 54

Pulmonary hemorrhage:

Back 54

anticoagulation, hemophilia, contusion, PE, vasculitis (Goodpasture’s, Wegener’s), CVD, infectious (TB, GNB, Aspergillus, Mucor), drugs, bronchiectasis, tumor

Front 55

HRCT: ground glass opacity

Back 55

hypersensitivity pneumonitis, all acute interstitial disease (IPF, viral), PCP, BOOP, eosinophilic PNA, pulmonary edema, alveolar proteinosis

Front 56

centrilobular nodules

Back 56

endobronchial spread of infection or tumor (TB, MAI, bronchoPNA), airways diseases (CF, bronchiectasis, TB, MAI), hypersensitivity pneumonitis, silicosis, histiocytosis, BOOP, pulmonary edema, talc

Front 57

tree-in-bud

Back 57

endobronchial spread of infection, airways diseases

Front 58

perilymphatic nodules

Back 58

sarcoid, silicosis, lymphangitic spread

Front 59

diffuse random nodules

Back 59

miliary TB, fungus, mets

Front 60

Kerley B lines:

Back 60

CHF, lymphangitic spread of CA; less common – viral, asbestosis, sarcoid, lymphoma

Front 61

Pulmonary fibrosis:

Back 61

IPF, sarcoid, pneumoconiosis, histiocytosis, CVD, talc, radiation, drugs, chronic hypersensitivity pneumonitis, NF

Front 62

Lymphangitic carcinomatosis:

Back 62

lung, breast, stomach, pancreas, prostate, thyroid

Front 63

Hematogenous pulmonary mets:

Back 63

lung, breast, kidney, thyroid, colon, uterus, head&neck, testes, melanoma, lymphoma, osteosarcoma

Front 64

Calcified nodules:

Back 64

thyroid mets, mucinous mets, osteogenic mets, varicella, TB, histo, cocci, silicosis, alveolar microlithiasis

Front 65

Eggshell calcifications in hilar nodes:

Back 65

silicosis, CWP, treated lymphoma, granulomatous dz, sarcoid (rare)

Front 66

Conglomerate masses:

Back 66

silicosis, CA, TB, fungus, sarcoid, berylliosis

Front 67

Hilar mass:

Back 67

bilateral + symmetric (TB, fungal, sarcoid, mets, lymphoma, silicosis, PA enlargement), bilateral + asymmetric (TB, fungal, sarcoid, mets, lymphoma, silicosis, PA enlargement), unilateral (TB, fungal, sarcoid, mets, lymphoma, lung CA, carcinoid Castleman’s, PA enlargement, bronchogenic cyst); (per UCSD -5 infections) – TB, Histo, Anthrax, Brucellosis, Plague

Front 68

Superior mediastinal mass:

Back 68

thyroid, adenopathy, cystic hygroma, lymphoma, mets, vascular, parathyroid

Front 69

Anterior mediastinal mass:

Back 69

thymic lesion (thymoma), lymphoma (Hodgkin’s), germ cell tumor (teratoma), thyroid (intrathoracic goiter), vascular (aneurysm), bronchogenic cyst, pericardial cyst, lymphangioma, hemangioma, lipoma, TB, fungus, sarcoid, mets

Front 70

Middle mediastinal mass:

Back 70

thyroid (intrathoracic goiter), esophageal lesion (leiomyoma, duplication cyst), bronchogenic cyst, pericardial cyst, vascular lesion (aneurysm, aberrant vessel), mets (head and neck, GU, breast, melanoma), lung CA (small cell), lymphoma, leukemia, KS, TB, fungus, sarcoid, hiatal hernia, Castleman’s disease

Front 71

Posterior mediastinal mass:

Back 71

neurogenic tumor (neurofibroma, schwannoma, ganglioneuroma, neuroblastoma, pheochromocytoma, paraganglioma), anterior or lateral thoracic meningocele, bronchogenic cyst, gastroenteric cyst, neuroenteric cyst, TB spine, paraspinal lymphoma, vascular, hematoma, extramedullary hematopoeisis, Bochdalak hernia, sequestration, mets, sarcoid

Front 72

Fatty mediastinal mass:

Back 72

mediastinal lipomatosis, hernia, lipoma, liposarcoma, thymolipoma, teratoma

Front 73

Densely enhancing mediastinal mass:

Back 73

vascular, hypervascular tumors, goiters, Castleman’s

Front 74

Cyst:

Back 74

traumatic cyst, hematoma cyst, bronchogenic cyst, hydatid cyst, emphysematous bullae, bronchiectasis, end-stage interstitial disease, sequestration, CAM, pneumatocele; small cystic dz – EG, LAM, cystic PCP, honeycombing, emphysema

Front 75

Air crescent sign in cavity:

Back 75

Aspergillus, Mucor, Actinomycosis, septic emboli, Klebsiella, TB, tumors (KS)

Front 76

Endobronchial:

Back 76

tumor (usu sq cell > small cell, carcinoid), mets, TB, hamartoma, papilloma, hemangioma, foreign body, mucus plug, trauma, broncholith

Front 77

Scarring:

Back 77

prior TB, prior pneumonia, prior PE, prior trauma, prior surgery, radiation, fibrosis

Front 78

Calcification:

Back 78

granuloma (TB, fungus), hamartoma, lung CA, vascular, pleural (asbestos exposure, prior pyothorax or hemothorax), sarcoid, silicosis, varicella, mitral stenosis, mets (bone tumor, mucinous tumors, post-chemotherapy), alveolar microlithiasis, parasites

Front 79

Air fluid level:

Back 79

lung (abscess, tumor, cyst), mediastinum (esophageal lesion, bronchogenic cyst), pleural (hydroPTX, hemoPTX, pyoPTX, bronchopleural fistula), hiatal hernia, achalasia,

Front 80

Atelectasis:

Back 80

poor diaphragmatic excursion, hypoventilation, PE; central obstruction – endobronchial mass (bronchogenic CA, mucus plug, foreign body), extrinsic mass (large lymph nodes, large heart, aneurysm, mediastinal mass); peripheral obstruction – pneumonia, post-surgery (LLL after cardiac surgery); compression – pleural effusion, PTX; contraction – scarring from chronic TB or any pulmonary fibrosis

Front 81

Complete opacification of one hemithorax:

Back 81

complete atelectasis (bronchogenic CA, mucus plug, ETT too low), large effusion (mets, lymphoma), prior pneumonectomy, malignant mesothelioma, unilateral pneumonia or pulmonary edema

Front 82

PTX:

Back 82

emphysema (ruptured bulla), trauma (rib puncture, ruptured bronchus), iatrogenic (line placement, thoracentesis), any chronic interstitial lung disease or pneumoconiosis, pulmonary fibrosis, spontaneous, ventilator, bronchopleural fistula, infection (Staph), neoplasm (metastatic osteosarcoma), LAM, EG, asthma, PCP, catamenial

Front 83

Pneumomediastinum:

Back 83

asthma, trauma, alveolar rupture, ruptured bronchus or esophagus, post endoscopy, Boerhaave syndrome, positive pressure ventilation, chest tube placement, ruptured abdominal viscus, post surgical, pneumo(retro)peritoneum

Front 84

Pleural effusion:

Back 84

infectious, tumor (lung CA, mets, lymphoma), CHF (R>L), nephrotic syndrome, renal failure, liver failure, post-surgery (L post-cardiac surgery), post-trauma, mesothelioma, asbestosis, ovarian CA (Meig’s syndrome), pancreatitis, Dressler syndrome, CVD, sarcoid, drugs, ascites, PE, leukemia

Front 85

Chylothorax:

Back 85

tumor (esp lymphoma), trauma, iatrogenic, idiopathic, LAM, filariasis

Front 86

Pleural mass:

Back 86

mesothelioma, benign fibrous tumor, malignant thymoma/lymphoma, mets (esp lung CA), lipoma, rib tumors (children – EG, ABC, Ewing’s, neuroblastoma; adults – mets>myeloma>Paget’s, fibrous dysplasia), neurofibromas, infection (TB, fungus, Actinomycosis), asbestos-related, trauma, surgery

Front 87

Calcified pleural plaques:

Back 87

TB, asbestos exposure, fluid (empyema, hematoma), talc

Front 88

Pleural thickening + calcification:

Back 88

old infection, old trauma, asbestos exposure, loculated effusion, empyema, pleural mets, mesothelioma, talc

Front 89

Extrapleural lesions:

Back 89

CA (mets, myeloma, esp rib mets), infection (TB, fungus, Actinomycosis), trauma (hematoma), diaphragmatic rupture or paralysis, pectus excavatum, kyphoscoliosis, cervical ribs, congenital fusion of ribs

Front 90

Elevated diaphragm:

Back 90

localized eventration, atelectasis, subpulmonic effusion, diaphragmatic paralysis, hernia (hiatal, Morgagni, Bochdalak), ascites, subphrenic mass, pleural mass

Front 91

Oligemia and/or overinflation:

Back 91

infection (TB, Staph pneumatocele, viral, parasite), pulmonary HTN, asthma, emphysema, bullae, lobar atelectasis with compensatory hyperinflation, Swyer-James-Macleod syndrome = bronchiolitis obliterans (unilateral hyperlucent lung), PE (Westermark’s sign), foreign body or mucus plug (air trapping), lung hypoplasia, scimitar syndrome, mastectomy, congenital bronchial atresia, congenital lobar emphysema, Poland’s syndrome (congenital absence of pectoralis muscle), PA stenosis/hypoplasia

Front 92

Bronchiolitis obliterans:

Back 92

postinfectious, CVD (esp RA), toxic fumes, post transplant (BMT), lymphoma, lung CA, idiopathic

Front 93

Mosaic attenuation (air trapping):

Back 93

BO, sarcoid, hypersensitivity pneumonitis, chronic PE, asthma, emphysema

Front 94

Small lung:

Back 94

hypogenetic lung syndrome, PA agenesis, chronic atelectasis, BO

Front 95

Small hilum:

Back 95

PA compression/invasion/hypoplasia, lobar atelectasis/resection, emphysema

Front 96

Enlarged cardiac silhouette:

Back 96

cardiomegaly, pericardial effusion

Front 97

Blunted CPA

Back 97

pleural effusion, pleural thickening

Front 98

SVC syndrome:

Back 98

bronchogenic CA (#1), lymphoma, mets, long term IV devices, fibrosing mediastinitis