temporal bone

Question 1

Answer 1

Classic EAC cholesteatoma. Axial bone algorithm shows soft tissue density within the medial left EAC with boney erosion and characteristic bone flakes.

Question 2

40 yo surfer

Answer 2

EAC exostosis

• benign overgrowth of bony EAC in response to chronic cold water exposure, typically surfers
• BILATERAL in all cases

Question 3

Answer 3

Keratosis obturans

Question 4

Answer 4

EAC osteoma. Focal penduculated overgrowth.

Question 5

Answer 5

Accessory ossicle

Axial bone CT shows an ovoid bone with cortex and marrow space in the location of the posterior portion of the cartilaginous EAC. No stalk of attachment is visible. Accessory ossicles are rare in this area.

Question 6

Answer 6

Congenital External and Middle Ear Malformation

Question 7

50yoM with diabetes.

Answer 7

Necrotizing external otitis

Classic inferior EAC osseous destruction and inflammatory tissue within the medial EAC.

Typical organism is pseudomonas aeruginosa.

95% of adults with NEO have diabetes

Question 8

Answer 8

Keratosis obturans.

Benign soft tissue mass filling and slightly expanding the EAC. No bony erosions.

Abnormal accumulation of keratin.

Question 9

Answer 9

SCC of the EAC on CT and MR

axial bone algorithm CT shows soft tissue density in the EAC with osseous erosion. MR demostrates soft tissue enhancement.

Bone destruction and soft tissue invasion = aggressive malignancy

Question 10

Answer 10

ME cholesteatoma, congenital.

Medial epitympanic congenital cholesteatoma that erodes portions of the ossicles.

Solid arrow: choleastatoma

open arrow: erosion of the long process of the incus and hub of the stapes

Curved arrow: erosion of the lateral bony margin of the tympanic segment of the facial nerve canal

Question 11

Answer 11

Oval window atresia

**Tympanic segment of the facial nerve will always be aberrant in the location of the oval window instead of inferior to the lateral semi-circular canal

Question 12

Answer 12

Prolapsing facial nerve (protruding intratemporal facial nerve)

Tubular soft tissue prolapsing into oval window niche from undersurface of LSC. Caused by dehiscence of bony covering of the facial nerve.

No enhancement! If enhances then it is a Schwannoma.

May project into oval indow.

Question 13

Answer 13

Question 14

Answer 14

Question 15

Answer 15

Question 16

Answer 16

Question 17

Answer 17

glomus jugulare

Question 18

Answer 18

acquired cholesteatoma in the epitympanum

Question 19

which semicircular canal gets eroded in the setting of an acuired cholesteatoma in the epitymapnic space?

Answer 19

lateral semicircular canal

Question 20

what is the association with this diagnosis?

Answer 20

endolymphatic sac tumor. associated with VHL

Question 21

what percent of VHL patients get endolymphatic sac tumors

Answer 21

15%

Question 22

Answer 22

otosclerosis (otospongiosis)

demineralization at the fissula ante fenestram

Question 23

in otosclerosis where does demineralization typically occur?

Answer 23

fissula ante fenestram

Question 24

s

Answer 24

Question 25

most common cause of hearing loss in kids?

Answer 25

large vestibular aqueduct syndome

Question 26

hearing loss NOT present at birth that starts in childhood and is progressive

Answer 26

large vestibular aqueduct syndrome

Question 27

upper limit of size of the vestibular aqueduct

Answer 27

1.5 mm

Question 28

Answer 28

Question 29

what other anatomic anomaly may be present in the following patient?

Answer 29

absence of the bony modialis occurs in about 90% of patients