Skull base/PPF

Question 1

boundaries of the PPF

Answer 1

maxillary sinus, inferior to orbital fissure

Question 2

contents of PPF

Answer 2

pterygopalatine ganglion, branches of internal maxillary artery

Question 3

foramina of the PPF

Answer 3

pterygomaxillary fissure, sphenopalatine foramen, foramen rotundum, inferior orbital fissure, vidian canal ,pterygopalatine canal

Question 4

anterior skull base

Answer 4

divides anterior cranial fossa from paranasal sinuses

contains cribriform plate

Question 5

anterior skull base neoplasms

Answer 5

juvenile nasopharyngeal angiofibroma (JNA); olfactory groove meningioma; esthesioneuroblastoma, SCC, adenoid cystic carcinoma, rhabdomyosarcoma

Question 6

juvenile nasopharyngeal angiofibroma (JNA)

Answer 6

benign vascular tumor in adolescent males; presents with nasal obstruction/epistaxis

locally aggressive and insinuates through adjacent skull base foramina

arises from nasal aspect of sphenopalatine foramen

Question 7

3 classic findings of JNA

Answer 7

nasopharyngeal mass, expansion of PPF, bowing of maxillary sinus wall

Question 8

imaging findings of JNA

Answer 8

avidly enhancing, centered in nasopharynx; extension into PPF or orbits

may undergo preo-op emoblization prior to resection

Question 9

olfactory groove meningioma

Answer 9

arises from archnoid villi rests; most common intracranial lesion in anterior skull base

avid enhancement, enhancing dural tail, reactive bone sclerosis

Question 10

esthesioneuroblastoma

Answer 10

olfactory neuroblastoma; malignant neural crest tumor from olfactory epithelium

bimodal age distribution: teens/middle aged

Question 11

imaging findings of esthesioneuroblastoma

Answer 11

pathognomonic: peripheral tumor cysts at margins of intracranial portion of the mass

aggressive mass slightly hyperattenuating on CT; intermediate intensity on T1/2 images due to high cellularity; calcifications

Question 12

squamous cell carcinoma –anterior skull base

Answer 12

most common malignancy of paranasal sinuses/nose

most common primary site: maxillary antrum

aggressive, enhancing mass with bony destruction

Question 13

ddx for SCC in the anterior skull base

Answer 13

differentiate from benign sinonasal polyposis or mucocele

Question 14

adenoid cystic carcinoma

Answer 14

arises from minor salivary glands of sinonasal cavity; spread into trigeminal nerve with enhancement

water signal on T1/2 images with enhancement

Question 15

rhabdomyosarcoma

Answer 15

most common head/neck tumor in children