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Acoustic Neuroma

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What is Acoustic Neuroma

Acoustic neuroma (also known as vestibular schwannoma, neurinoma, neuromas) is a benign tumour (non malignant) of the Schwann cells (insulating cells) that surround the vestibulocochlear (XIIth) cranial nerve. The XII nerve sits within the temporal bone in the skull. Acoustic neuroma is responsible for balance and hearing as it relays nerve impulses from the cochlea (the organ of hearing).

Below is an MRI scan image of a person who has developed an acoustic neuroma:

Acoustic neuroma MRI image

Statistics on Acoustic Neuroma

Acoustic neuromas occur throughout the world. No ethnic groups are affected disproportionately. Symptomatic neuromas are estimated to effect 1 in every 3,500 to 5 in every million people. Acoustic neuromas more common in men and between the ages of 30-60 years.

Risk Factors for Acoustic Neuroma

The cause of acoustic neuroma is unknown. A small proportion of people also have neurofibromatosis type 2 (a hereditary condition).

Progression of Acoustic Neuroma

Acoustic neuromas are very slow growing. Acoustic neuromas generally originate within the internal auditory canal and may cause bony erosion as they expand. The acoustic neuroma tumour will compress the XIIth (vestibular cochlear) then VIIth (facial) cranial nerves and effect their function. A untreated acoustic neuroma tumour will protrude further into the brain and may eventually compromise other nerves and brainstem function.

How is Acoustic Neuroma Diagnosed?

To investigate acoustic neuroma, hearing tests are performed including routine audiological tests and speech discrimination.

Prognosis of Acoustic Neuroma

Prognosis of acoustic neuroma depends upon the size of the tumour and the extent of its growth. Most are fully resectable, however some acoustic neuroma symptoms may remain post operatively.

How is Acoustic Neuroma Treated?

Observation is recommended in patients with asymptomatic neuromas or in patients who are high risk for surgery. Observation includes regular MRI. Acoustic neuroma surgery is the only way to remove the tumour completely. Microsurgery allows preservation of hearing when resecting small tumours. Acoustic neuroma patients are monitored in intensive care post operatively to avoid complications. Stereotactic radiation therapy (radiation surgery) is a option for acoustic neuroma patients who are high risk for surgery, have small tumours or tumours on both sides.

Acoustic Neuroma References

  1. Acoustic neuroma [online]. Minneapolis, MN: University of Minnesota; 2002 [cited 11 August 2002]. Available from: URL link

Dates

Posted On: 11 August, 2002
Modified On: 14 June, 2015
Reviewed On: 5 February, 2007

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