Vestibular Schwannomas (Acoustic Neuroma)

Question 1

What type of tumour is a vestibular schwannoma?

Answer 1

A benign brain tumour that usually grows slowly and does not spread

Question 2

What nerve do they grow on?

Answer 2

Vestibulocochlear nerve (CN VIII)
From the Schwann cells covering the the nerve
Schwann cells = the principle glia cells of the PNS

Question 3

What age do they typically occur?

Answer 3

30 to 60

Question 4

What causes them?

Answer 4

No obvious cause

Small number may be due to neurofibromatosis type 2 (genetic condition) - bilateral vestibular schwannomas

Question 5

What symptoms occur?

Answer 5

Classic: vertigo, sensorineural hearing loss, tinnitus, absent corneal reflex
VIII: vertigo, unilateral sensorineural hearing loss, unilateral tinnitus
V: absent corneal reflex
VII: facial palsy

Question 6

Large tumours can cause…

Answer 6

Raised ICP signs

Ipsilateral cerebellar signs e.g ataxia

Question 7

How do they cause problems?

Answer 7

By local pressure

Behaving as a space occupying lesion

Question 8

What tests are required?

Answer 8

Hearing tests - audiogram
MRI (gadolinium enhanced)
MRI preferred over CT as CT can miss small tumours
MRI of the cerebellopontine angle

Question 9

The symptoms can be confused with…

Answer 9

Ménière’s disease

Question 10

How is it managed?

Answer 10

Monitoring - especially if small
Surgery to remove tumour
Stereotactic radiosurgery

Surgery may not be needed especially if elderly as it can be a difficult procedure

Question 11

Large tumours can cause…

Answer 11

Hydrocephalus - but rare to reach this stage

Due to pressure on brainstem - preventing flow of CSF

Question 12

Can it return after treatment?

Answer 12

Yes - 1 in 20 do

Question 13

Do the signs and symptoms occur gradually or suddenly?

Answer 13

Gradually