Acoustic Neuroma

Question 1

What is the definition of acoustic neuroma?

Answer 1

Rare, benign tumour of CN VIII sheath that arises in internal auditory meatus.

Question 2

What are some risk factors for acoustic neuroma?

Answer 2

May be associated with extensive exposure to loud noise
Neurofibromatosis type 2 (if bilateral and young)

(however 95% are sporadic and unilateral)

Question 3

What is the pathophysiology of acoustic neuroma?

Answer 3

Associated with vestibular portion of CN VIII and occurs within temporal bone
Represent 80-90% of cerebellopontine angle tumours

Question 4

What is the gross appearance of acoustic neuroma?

Answer 4

Circumscribed tan/white/yellow mass

Question 5

What is the histological appearance of acoustic neuroma?

Answer 5

Encapsulated
Two growth patterns (Antoni A and Antoni B)

Question 6

What are some clinical features of acoustic neuroma?

Answer 6

Progressive sensorineural unilateral hearing loss and tinnitus
Imbalance in larger tumours
Facial numbness due to compression of trigeminal nerve as tumour enlarges

Question 7

What are some investigations for acoustic neuroma?

Answer 7

MRI

Question 8

What is the management of acoustic neuroma?

Answer 8

Surgical excision (definitive)
Monitoring with MRI at 6 month interval for small lesions that are not growing