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240 Cards in this Set
- Front
- Back
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Most common disease of the paranasal sinuses?
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Inflammatory disease
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What characterizes acute sinusitis?
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Air-fluid levels
Foamy appearing sinus secretions |
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What characterizes chronic sinusitis?
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Mucoperiosteal thickening without bony expansion
Osseous thickening of the sinus walls |
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MR findings in sinusitis?
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High signal on T2WIs
BUT, desicated secretions in chronic sinusitis may not have signal |
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Disease in the infundibulum of the maxillary ostium will result in:
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Opacification of the maxillary sinus
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What structure is crucial for mucociliary drainage?
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The ostiomeatal unit
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What will happen if there is obstruction of the hiatus semilunaris (the middle meatus)?
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Combined obstruction of the ipsilateral maxillary, anterior and middle ethmoid air cells, and the frontal sinus
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What should you think about when you see opacification of the maxillary, anterior and middle ethmoid air cells and frontal sinuses?
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You should try to identify the offending lesion within the hiatus semilunaris, rather than simply describing the presence of diffuse sinus disease.
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Complications of sinusitis?
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Inflammatory polyps, mucous retention cysts, mucoceles
Cavernous sinus thrombosis is the most important complication |
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Why do inflammatory polyps form in the sinus?
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Chronic inflammation leads to mucosal hyperplasia and redundancy
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What is an antrochoanal polyp?
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When a maxillary antral polyp expands to the point where it prolapses through the sinus ostium
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What does an antrochoanal polyp look like on CT?
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-Soft tissue mass extending from the maxillary sinus to fill the ipsilateral nasal cavity and nasopharynx
-Often the ostium of the maxillary sinus will be enlarged secondary to the mass effect of the polyp -Peripheral enhancement without any central enhancement |
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Why is it important to differentiate a nasal polyp from a antrochoanal polyp?
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Because if an antrochoanal polyp is snared and removed like a nasal polyp without regard for its antral stalk, it will recur
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What is a mucous retention cyst?
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Obstructed mucous gland within the mucosal lining
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What do mucous retention cysts look like?
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-Characteristic rounded appearance
-Measure one to several centimeters in diameter |
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What is a mucocele?
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-Similar to a retention cyst, but instead of a single mucous gland becoming obstructed, the entire sinus is obstructed
-Typically occurs because of a mass obstructing the draining sinus ostium |
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What do mucoceles look like?
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Frank expansion of the sinus with associated smooth sinus wall bony thinning and remodeling
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Which sinus is most commonly affected by mucous retention cysts?
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Maxillary
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Which sinus is most commonly affected by mucoceles?
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Frontal
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What is an infected mucocele called?
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A mucopyocele
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What does an infected mucocele look like?
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Like a mucocele with peripheral enhancement
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Where do inverting papillomas tend to occur?
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Almost exclusively on the lateral nasal wall
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What is an inverted papilloma?
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-Named based on their histologic appearance
-The neoplastic nasal epithelium inverts and grows into the underlying mucosa -NOT associated with allergy or infection |
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How is an inverted papilloma treated?
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It should be resected with wide mucosal margins
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Why should inverted papillomas be resected?
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They're associated with squamous cell carcinoma
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What does an inverted papilloma look like?
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-Enhancing mass centered in the middle meatus
-Local bony remodeling & ostiomeatal unit opacification -“cerebriform pattern” |
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What should you think of in a teenage male with epistaxis?
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Juvenile nasopharyngeal angiofibroma
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Why is it super important to diagnose a JNA off of imaging?
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Because life threatening hemorrhage can result if these things are biopsied or if limited resection is attempted
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Is a JNA benign or malignant?
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Benign tumor that can be locally aggressive
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What tissue do JNAs arise from?
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The fibrovascular stroma of the nasal wall adjacent to the sphenopalatine foramen
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What do JNA’s look like?
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-Location in the retromaxillary pterygopalatine fossa is a hallmark (if you see something in this location, think about JNA)
-They characteristically fill the nasopharynx and bow the posterior wall of the maxillary sinus forward -They enhance markedly which differentiates them from the rarer lymphangioma |
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How are JNA’s managed?
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NeuroIR often embolizes them before surgery
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Symptoms of paranasal sinus squamous cell cancer?
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-It is often clinically silent until it is quite advanced
-Early symptoms are related to obstructive sinusitis |
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Imaging findings in paranasal sinus squamous cell cancer?
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-Opacified sinus with associated bony wall destruction
-These findings are nonspecific and do not allow differentiation from non-Hodgkin’s lymphoma or a minor salivary gland malignancy |
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Differential for opacified sinus with bony wall destruction?
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-Squamous cell cancer
-Non-Hodgkin’s lymphoma -Minor salivary gland malignancy -Mucopyocele with osteomyelitis |
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How does lymphoma of the paranasal sinuses present?
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Constitutional symptoms with prominent hand and neck or systemic adenopathy, especially in a child or young adult
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Where are the minor salivary glands located?
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Throughout the upper aerodigestive tract but are most highly concentrated in the palate
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Are minor salivary gland tumors usually benign or malignant?
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Malignant
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Are parotid salivary gland tumors usually benign or malignant?
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Benign
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What types of cancers arise from salivary glands?
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Adenoid cystic carcinoma
Adenocarcinoma Mucoepidermoid carcinoma |
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What is an esthesioneuroblastoma?
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A tumor that arises from neurosensory receptor cells of the olfactory nerve and mucosa
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Where are esthesioneuroblastomas located?
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-Anywhere from the cribiform plate to the turbinates
-Usually high in the nasal vault -Involvement of the cribiform plate with extension into the anterior cranial fossa is not uncommon |
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How can you tell a sinonasal tumor apart from the associated obstructed sinus secretions?
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-Heavily T2W images help because sinus secretions will be brighter than the malignancy
-The malignancy is often isointense with respect to muscle |
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Name the five bones of the skull base:
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Ethmoid
Sphenoid Occipital Temporal Frontal |
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Are most skull bases lesions primary or metastatic?
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Metastatic
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Three most common primary tumors of the skull base?
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Chordoma
Chondrosarcoma Osteogenic sarcoma |
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What is a chordoma?
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It is a neoplasm that arises from remnants of the primitive notochord
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Where can chordomas be found?
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Anywhere along the craniospinal axis
35% involve the clivus 50% involve the sacrum 15% involve the vertebral bodies |
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How do chordomas classically present in the skull base?
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-As a destructive midline lesion of the clivus
-It has a predilection for the sphenooccipital synchondrosis -Sagittal images show tumor “thumb” indenting pons -Calcification, hemorrhage, retained bony fragments, mucoid material give tumor heterogeneous appearance |
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What is a chondrosarcoma?
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Malignant tumor that develops from cartilage
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Why would the skull base be prone to chondrosarcoma?
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It was preformed from cartilage
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Where do chondrosarcomas like to form in the skull base?
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They prefer the petroclival junction
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Risk factors for osteosarcoma of the skull base?
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Prior radiation or Paget’s disease
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So, a midline clival destructive lesion=
And a paraclival destructive lesion= |
=Chordoma
=Chondrosarcoma |
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What CT characteristics would tell you that a clival lesion might be fibrous dysplasia?
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-Smooth, gound-glass appearance
-No bony destruction |
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What CT characteristics would tell you that a clival lesion might be Paget’s?
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-Trabecular coarsening
-No bony destruction |
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Most common lesion of the jugular foramen?
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Paraganglioma
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Presenting symptoms of a jugular foramen paraganglioma?
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Tinnitus, conductive hearing loss
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MR findings in paraganglioma?
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-“salt and pepper” signal due to numerous flow voids
-Widening of the jugular foramen |
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What things pass through the jugular foramen?
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-Cranial nerves IX, X, XI (remember the jug?)
-Sigmoid sinus -Posterior meningeal artery |
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What lesions arise from the cranial nerves passing through the jugular foramen?
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CNIX: schwannoma
CNX: paragangliomas CNXI: schwannoma |
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What is a cholesteatoma?
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Epidermoid cyst composed of desquamating stratified squamous epithelium
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Why do cholesteatomas enlarge?
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Because of progressive accumulation of epithelial debris within their lumen
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How do congenital cholesteatomas develop?
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From epithelial rests within or adjacent to the temporal bone
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What specific tissue gives rise to acquired cholesteatomas?
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The stratified squamous epithelium of the tympanic membrane
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Imaging findings in cholesteatomas?
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-Soft tissue mass in the middle ear cavity
-Typically has associated bony erosion -Classic: soft tissue in the middle ear with subtle bony erosion of the scutum and medial displacement of the ossicles |
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What is the name of the space that is the superior recess of the tympanic membrane in the middle ear?
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Prussak space
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What foramen does the facial nerve exit through inferiorly in the middle ear?
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The stylomastoid foramen
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The stapes connects to which window?
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The oval window
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What's the name of the bone that covers the top of the middle and inner ear?
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Tegmen tympani
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Bony prominence that connects to the top part of the tympanic membrane?
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Scutum
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Why is the upper part of the tympanic membrane more prone to cholesteatomas?
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Because it retracts easily
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How can you differentiate otitis media from a cholesteatoma?
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You can’t; they have similar densities
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What does the ENT want to know about a cholesteatoma when he orders a CT?
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-How big it is
-The status of the ossicles, the labyrinth, the tegmen, and the facial nerve. |
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What is a cholesterol granuloma?
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-Type of granulation tissue that may involve the petrous apex
-These lesions represent petrous apex air cells that have become partially obstructed and are filled with cholesterol debris and hemorrhagic fluid |
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What do cholesterol granulomas of the petrous apex look like on MR?
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They are characteristically high signal on both T1 and T2
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Differential for opacified petrous apex?
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Retained fluid secretions
Petrous apicitis Nonaerated petrous apex |
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Differentiating feature of retained fluid secretions in the petrous apex?
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-Parallels signal intensity of fluid
-Dark T1, bright T2, no enhancement |
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Differentiating feature of petrous apicitis?
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-Parallels signal intensity of an abscess
-Dark T1, bright T2, ring enhancement |
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Differentiating feature of a nonaerated petrous apex?
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-Parallels signal intensity of fatty bone marrow
-Bright T1, dark T2, no enhancement |
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Are pediatric neck masses more likely benign or malignant?
What types of cancers present this way? |
-Benign congenital or inflammatory lesions
-If it’s cancer, it’s likely lymphoma (Burkitt lymphoma if rapid growth is noted) or rhabdomyosarcoma |
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Are adult neck masses more likely benign or malignant?
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Malignant, except thyroid lesions
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What are the borders of the nasopharynx?
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-Inferior: hard and soft palates
-Posterior: pharyngeal constrictor muscles -Anterior: nasal choana |
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What separates the oral cavity and the oropharynx?
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The circumvallate papillae, tonsillar pillars, and the soft palate
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Can you name the seven spaces in the deep cervical fascia?
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Superficial mucosal
Parapharyngeal Carotid Parotid Masticator Retropharyngeal Prevertebral |
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Why are the deep cervical fascial spaces important?
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Because if you know which space a lesion is in, and you know what normally lives in that space, you can figure out what sort of lesion it is!
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What is in the deep cervical fascia mucosal space?
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Squamous mucosa
Lymphoid tissue Minor salivary glands |
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What is in the deep cervical fascia parapharyngeal space?
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-Fat
-Trigeminal nerve (V3) -Internal maxillary artery -Ascending pharyngeal artery |
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What is in the deep cervical fascia parotid space?
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-Parotid gland
-Intraparotid lymph nodes -Facial nerve (7) -External carotid artery -Retromandibular vein |
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What is normally in the carotid space?
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-Cranial nerves IX, X, XI, XII
-Sympathetic nerves -Jugular chain nodes -Carotid artery -Jugular vein |
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What structures are in the masticator space?
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-Muscles of mastication
-Ramus and body of the mandible -Inferior alveolar nerve |
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What structures are in the retropharyngeal space?
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-Lymph nodes (lateral and medial retropharyngeal)
-Fat |
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What structures are in the prevertebral space?
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-Cervical vertebrae
-Prevertebral muscles -Paraspinal muscles -Phrenic nerve |
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What is the pharyngobasilar fascia?
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-The aponeurosis of the superior pharyngeal constrictor muscles, which insets into the skull base
-This tough fascia separates the mucosal space from the surrounding parapharyngeal space |
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What are the most common benign lesions of the mucosal space?
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Tornwaldt cysts and minor salivary gland lesions
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What is a Tornwaldt cyst?
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-Thought to be remnants of notochordal tissue
-1-2% in normal pts |
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What do Tornwaldt cysts look like?
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-Midline
-High T2 signal |
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What does a pleomorphic adenoma look like?
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Well circumscribed, rounded lesions that have high signal intensity on T2
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What are the three most common malignancies of the mucosal space?
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-Squamous cell ca.
-Non-Hodgkin lymphoma -Minor salivary gland neoplasms -Unfortunately, these all appear similar on CT and MR |
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Imaging findings in mucosal space cancers?
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-Mass effect, often associated with lateral compression or obliteration of the parapharyngeal space, followed by invasion of the skull base
An early triad consists of: -Superficial nasopharyngeal mucosal asymmetry -Ipsilateral retropharyngeal adenopathy -Mastoid opacification(early warning sign) |
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What does mastoid opacification indicate?
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-Dysfunction of the eustachian tube, frequently the result of tumor invasion of the tensor veli palatini muscles
-This findings should cause you to carefully evaluate the mucosa of the nasopharynx |
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Which MR sequences are most helpful in evaluating for cancer of the nasopharynx?
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Fat suppressed T2 and contrast enhanced sequences
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What tumor of the mucosal space has a propensity for perineural invasion?
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Adenoid cystic carcinoma
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What makes nasopharyngeal carcinoma different from regular squamous cell carcinoma?
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-It is a particular variant of squamous cell that has unique features
-Much more common in Asian countries -Not associated with smoking or alcohol -Associated with Epstein Barr virus |
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What would make you worry that mucosal lesion is a lymphoma?
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-Systemic manifestations
-Bulky supraclavicular and mediastinal adenopathy -Splenomegaly |
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What are the cranio-caudal borders of the parapharyngeal space?
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It extends from the skull base to the submandibular gland
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What spaces border the parapharyngeal space?
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Medial: mucosal space
Lateral: parotid Anterior: masticator Posterior: carotid |
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What is the stylomandibular notch?
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Angle that the styloid makes with the mandible
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Masses in the carotid space will do what to the stylomandibular notch?
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They will narrow it (because they displace the styloid anteriorly)
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Which internal jugular vein is usually larger?
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The right
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What cells do paragangliomas arise from?
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Neural crest cells
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What are the different types of paragangliomas?
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-Carotid body tumors (at the carotid bifurcation)
-Glomus vagale (at the vagus nerve ganglion) -Glomus jugulare (along the jugular ganglion of the vagus nerve) -Glomus tympanicum (Arnold and Jacobson nerves in the middle ear) |
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Symptoms of paraganglioma?
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-Painless, slowly progressive neck mass
-Pulsatile, may have associated bruit -Because they are in the carotid space, they are often associated with slowly progressive cranial neuropathies |
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What should you look for if you see a paraganglioma?
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More paragangliomas, they are often multiple (5-10%)
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Why does neuroIR get involved in the management of paragangliomas?
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They do pre-op embolizations, reducing blood loss during surgery
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Imaging findings in paragangliomas and schwannomas?
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-Both are densely enhancing, and typically indistinguishable
-Paragangliomas have lots of flow voids, “salt and pepper” -Schwannomas usually do not demonstrate flow voids and can be cystic BUT very vascular schwannomas may have flow voids |
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Describe schwannomas:
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-Arise from the nerve sheath covering
-Do not infiltrate the substance of the nerve -May occasionally show cystic change |
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How do neurofibromas look different from schwannomas?
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-They are not encapsulated
-They often involve multiple peripheral nerves -They permeate the substance of the nerve fibers -They have a characteristic low intensity center on T1 |
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Most common malignancy of the carotid space?
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Nodal metastases
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How would a mass in the deep lobe of the parotid gland deviate the parapharyngeal space?
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Medially
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How would a mass in the parotid space deviate the styloid process?
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Posteriorly , widening the stylomastoid foramen
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Most common parotid gland tumor?
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Mixed cell tumors (pleomorphic adenomas)
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Second most common parotid gland tumor?
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Warthin tumors (benign)
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Can we tell benign from malignant parotid tumors?
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No, but pleomorphic adenomas have characteristic features
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What do pleomorphic adenomas look like?
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-Well circumscribed
-Very bright on T2 -Heterogeneous enhancement |
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What characteristics would be concerning for parotid malignancy?
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-Tumor homogeneity
-Indistinct margins -Indistinct signal intensity -Infiltration into deep neck structures -Involvement of the facial nerve |
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How often are Warthin tumors multiple?
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10%
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What is thought to cause Parotid cysts?
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Partial obstruction of the salivary ducts by surrounding lymphocytic infiltration
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What pts are prone to getting parotid cysts?
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AIDS and collagen vascular disease pts
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Muscles of mastication?
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Temporalis
Medial pterygoid Lateral pterygoid Masseter |
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Where are accessory parotid glands found?
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-Along the anterior surface of the masseter
-These can be mistaken for a mass |
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How could tumor spread from the masticator space into the cavernous sinus?
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It can spread along the third division of the trigeminal nerve, though the foramen ovale
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What spaces does the retropharyngeal space lie between?
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The mucosal space and the prevertebral space
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How can you tell a mass is in the retropharyngeal space, and not in the prevertebral or mucosal spaces?
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It will displace the prevertebral muscles posteriorly
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The lateral retropharyngeal nodes are also known as:
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The nodes of Rouviere
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Should you see lateral retropharyngeal nodes normally?
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-Yes if a patient is younger than 30
-If they’re older than 30, you should be suspicious |
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How can you tell an abscess from cellulitis on MR?
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-An abscess will demonstrate a rim of contrast enhancement surrounding a liquefied center.
-Cellulitis won’t -Both are isointense to muscle on T1 and bright on T2 |
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What processes are seen in the prevertebral space?
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Anything involving the cervical vertebrae (tumor, osteo)
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What do lymphangiomas and hemangiomas look like on MR?
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-They look similar
-Increased signal on T2 -Infiltrative |
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How can you tell a hemangioma apart from a lymphangioma?
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-Hemangiomas can have phleboliths on CT
-Lymphangiomas tend to heterogeneous signal with evidence of blood degradation products |
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Which diseases like to spread perineurally?
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Fungal infections, squamous cell ca., adenoid cystic carcinoma
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What is the highest node in the jugular chain called?
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The jugulodigastric lymph node
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Where is the jugulodigastric node located?
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-Where the posterior belly of the digastric muscle crosses the chain, near the level of the hyoid bone
-Immediately posterior to the submandibular gland |
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What nodal diameters are considered abnormal?
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-The jugulodigastric node and submandibylar nodes may normally measure up to 1.5cm in diameter
-All other nodes of the head and neck are considered abnormal if larger than 1 cm |
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What features of a lymph node suggest malignancy?
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-Peripheral nodal enhancement with central necrosis
-Extracapsular spread with infiltration of adjacent tissues -Matted conglomerate mass of nodes BUT the above features are also seen in infection—you cannot tell malignancy apart from infection. Clinical history's super-important there. -A round shape without a normal fatty hilum suggests neoplastic infiltration |
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What do normal lymph nodes look like on MR?
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They have homogeneous signal on all sequences
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What to optic nerve gliomas look like?
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-Enlarged optic nerve sheath complex
-May be tubular, fusiform, or eccentric with kinking -Some have extensive associated thickening of the perioptic meninges (termed arachnoidal hyperplasia or gliomatosis) |
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Optic nerve gliomas are associated with:
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Neurofibromatosis type 1, particularly when there are bilateral optic nerve gliomas
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What are optic sheath meningiomas?
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They arise from hemangioendothelial cells of the arachnoid layer of the optic nerve sheath
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What do metastatic lymph nodes look like on MR?
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Any heterogeneity in signal, especially in the presence of cystic change or necrosis, is consistent with metastasis
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The extraconal and intraconal spaces are contained in what space?
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The retrobulbar space
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What surrounds the optic nerve?
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-The optic nerve sheath complex
-Composed of CSF surrounded by leptomeninges -The optic nerve is an extension of the brain |
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Most common lesions of the optic nerve sheath complex?
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Optic nerve gliomas and optic sheath meningiomas
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What do optic sheath meningiomas look like? How can you tell them apart from optic nerve gliomas?
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-They assume a circular configuration
-They grow in a linear fashion along the optic nerve -They demonstrate a characteristic “tram track” pattern of linear contrast enhancement because the nerve sheath enhances rather than the nerve itself -In contrast to optic nerve gliomas, meningiomas may invade and grow through the dura, resulting in an irregular and asymmetric appearance. -Optic nerve sheath meningiomas may extensively calcify, whereas optic nerve gliomas rarely have any calcification. |
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What things might look like an optic nerve sheath meningioma?
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-Infiltrates from sarcoid, leukemia, or lymphoma
-These may have “tram track” enhancement -Optic neuritis has abnormal T2 hyperintensity and contrast enhancement |
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What vascular lesions are common to the orbit?
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-Capillary hemangiomas
-Lymphangiomas -Cavernous hemangiomas |
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Describe orbital capillary hemangiomas: What do they look like? Who gets them?
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-Develop in infants
-May grow rapidly in size -Typically plateau during the first year or two then spontaneously regress -Infiltrative soft tissue complex -Multiple vascular flow voids |
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Describe orbital lymphangiomas:
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-One of the most common orbital tumors of childhood
-Occur in children 3-15 years -Noted by their propensity to bleed -An acute hemorrhage can result in proptosis |
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What do orbital lymphangiomas look like?
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MR reveals multiloculated, lobular mass with characteristic signal heterogeneity caused by blood degradation products (this distinguishes them from capillary hemangiomas)
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Describe orbital cavernous hemangiomas: What do they look like?
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-One of the most common orbital masses in adults
-Shaply circumscribed, rounded mass -Diffusely enhance, sometimes mottled apearance |
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What does an orbital venous varix look like?
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-Enormously dilated vein
-Characterized by marked change in size with Valsalva maneuver |
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What would cause enlargement of the superior ophthalmic vein?
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-Cavernous sinus thrombosis
-Cavernous-carotid fistulas |
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How do patients with cavernous-carotid fistulas present?
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Pulsating exophthalmos and bruit
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Types of carotid-cavernous fistulas?
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-Direct or indirect
-Spontaneous or posttraumatic |
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What are the three most common orbital masses in adults (in order of prevalence)?
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-Pseudotumor
-Cavernous hemangioma -Lymphoma |
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What is pseudotumor of the orbit?
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-Long name=idiopathic inflammatory pseudotumor
-Most common cause of an intraorbital mass in adults -Poorly understood -Inflammatory lymphocytic infiltrate around the orbit |
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How do pseudotumor present?
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-Rapidly developing painful proptosis
-Chemosis—swelling of the conjunctiva -Ophthalmoplegia |
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How does lymphoma of the orbit present clinically?
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Painless proptosis
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What do orbital pseudotumor and lymphoma look like?
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-They can look exactly the same (one will be painfull, the other painless)
-Diffusely infiltrating lesions involving and extending into any retrobulbar structures -It is suggested that T2 hypointensity is suggestive of pseudotumor -Infiltrating lesions do NOT enlarge the tendinous attachments of the extraocular muscles while pseudotumor does. |
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What do you have to add to the differential if you see a diffusely infiltrative mass anywhere in the head and neck region in a child?
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Rhabdomyosarcoma
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What does thyroid ophthalmopathy look like?
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-Unilateral or bilateral proptosis
-Inflammatory infiltration of the orbital muscles and orbital connective tissues -Enlargement of the extraocular muscles with sparing of the tendinous attachments to the globe -80% have bilateral extraocular muscle involvement In some cases, the extraocular muscles are notmal and exophthalmos is caused by increased retrobulbar fat. |
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Which extraocular muscles are involved with Graves ophthalmopathy?
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"IM SLOW"
Inferior rectus Medial rectus Superior rectus Lateral rectus |
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What things are in the extraconal space?
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-Fat
-Lacrimal gland |
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What kinds of lacrimal gland neoplasms are there?
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Epithelial
-Benign mixed-cell tumor -Adenoid cystic carcinoma Lymphoid -Lymphoma -Pseudotumor |
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What does a lacrimal gland dermoid look like?
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A mass with a fat-fluid level
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How does retinoblastoma present?
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Leukocoria
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What does retinoblastoma look like?
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Calcified ocular mass
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Most common cause of a neck mass in a child?
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Thyroglossal duct cyst
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Where does the thyroglossal duct originate?
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The foramen cecum at the base of the tongue
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When does the thyroglossal duct normally involute?
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-8-10 weeks of gestation
-Any portion that fails to involute may give rise to a cyst or sinus tract -Thyroid glandular tissue can arrest anywhere along the course of the thyroglossal duct, giving rise to ectopic thyroid tissue |
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What percent of thyroglossal duct cysts are midline?
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75%
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Where are most thyroglossal duct cysts located cranio-caudally?
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At or below the level of the hyoid bone
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Why are thyroglossal duct cysts treated surgically?
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Because they tend to get infected
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Why is it so important to determine the full extent of the thyroglossal duct cyst before surgery?
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Because they tend to recur if incompletely resected
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What do thyroglossal duct cysts look like?
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-Cystic masses with a uniformly thin peripheral rim of capsular enhancement
-Occasional septations |
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Differential for a suspected thyroglossal duct cyst?
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-Necrotic anterior cervical nodes
-Thrombosed anterior jugular vein -Abscess -Obstructed laryngocele |
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What is a laryngocele?
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-The laryngeal ventricle separates the false and true cords and anteriorly ends in a blind pouch called the appendix
-A laryngocele develops are a consequence of chronically increased intraglottic pressure (musicians playing wind instruments, glass blowers, etc.) |
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Where is an internal laryngocele located?
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They are confined to the larynx
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Where is an external laryngocele located?
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-They protrude above the thyroid cartilage and through the thyrohyoid membrane
-These typically present as a lateral neck mass near the hyoid bone |
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What should you think about if you see a laryngocele in a person that doesn’t have any predisposing factors?
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You should be suspicious for an underlying neoplasm obstructing the laryngeal ventricle
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Which branchial cleft gives rise to the most abnormalities?
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The second
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Where is the second branchial cleft located?
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-It begins at the base of the tonsillar fossa and extends between the internal and external carotid arteries
-It is anterior to the middle portion of the sternocleidomastoid muscle and lateral to the internal jugular vein at the level of the carotid bifurcation |
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What do branchial cleft cysts look like?
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-Well-circumscribed cystic lesions
-Wall thickening, irregularity and enhancement are related to active or prior infections |
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Branchial cleft cysts can be hyper and hypointense on T1, why?
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The signal is related to proteinaceous cyst contents
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Types of lymphangiomas?
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-Capillary—composed of capillary sized thin walled vessels
-Cavernous—moderatly dilated lymphatics with fibrous adventitia -Cystic hygromas—enormously dilated lymphatic channels |
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How are lymphangiomas formed?
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-If primitive lymphatic sacs fail to communicate with the venous system, they dilate as they accumulate lymphatic fluid
-Thus, lymphangiomas represent sequestrations of the primitive embryonic lymph sacs -Extensive defects in the lymphovenous communication are incompatible with life and result in fetal hydrops |
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What syndromes are associated with cystic hygromas?
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Turners syndrome, fetal alcohol syndrome, Noonan syndrome, several chromosomal aneuploidies
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How do lymphangiomas and cystic hygromas present?
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-Painless compressible neck masses that can transilluminate if large enough
-Often occur in the posterior triangle of the neck |
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What do lympangiomas and cystic hygromas look like?
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-Multiloculated cystic masses with septations
-They have a propensity to hemorrhage into themselves -Associated with hemorrhage-fluid level or heterogeneous signal associated with blood degradation products -Associated with an acute, dramatic increase in size -They tend not to displace adjacent soft tissue structures -This may prove helpful in differentiating between other cystic structures, like necrotic lymph nodes. |
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FIGURE 9.30. Lymphangioma. Axial T2WI reveals a cystic retrobulbar lesion (arrows) with a hematocrit effect (serum layered above red blood cells). Hemorrhage into a lesion is a characteristic feature of lymphangiomas and may be responsible for the rapid development of proptosis.
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