- Slow-growing benign tumor, most often arising from the vestibular division of 8th cranial nerve
- Originates from Schwann cells of the nerve sheath (“schwannoma”)
- Usually arises in the internal auditory canal near the cerebellopontine angle
- Often has extracanalicular portion into the cerebellopontine angle, but may also stay purely intracanalicular
- Most are unilateral; bilateral only seen in neurofibromatosis type II
- 6–10% of all intracranial tumors
- 80–90% of cerebellopontine angle tumors
- 95% of cases are unilateral
- Present most commonly in the 5th–6th decade
- Female predominance
- Bilateral acoustic neuroma occurring in neurofibromatosis II present before age 30
- 1/100,000 per year
- Asymptomatic lesions may be more common
3,000 diagnosed annually in the US
- Pregnancy and epilepsy may increase risk (1).
- Smoking may decrease the risk (1).
- Unknown for unilateral acoustic neuroma (AN)
- Neurofibromatosis type II: Bilateral ANs:
- Autosomal dominant
- Gene located on chromosome 22q1
- Exerts pressure on the surrounding structures
- Compression of acoustic and facial nerve when located within internal acoustic canal
- Compression of brainstem, 4th ventricle, and trigeminal nerve when tumor at the cerebellar pontine angle
Commonly Associated Conditions
- Neurofibromatosis type II
- Pregnancy may accelerate the growth of the tumor
Acoustic Neuroma is a sample topic found in
5-Minute Clinical Consult .
To find other 5-Minute Clinical Consult topics
please login or purchase a subscription.