An acoustic neuroma is a rare, usually slow-growing tumor of the inner ear, specifically of the nerve that connects the ear to the brain (the hearing nerve). Despite usually being benign, an acoustic neuroma that grows and is not treated can severely affect neurological function and become life-threatening.
An acoustic neuroma is also called vestibular schwannoma, neurinoma, or neurilemmoma.
This type of brain tumor develops in the eighth cranial nerve, which controls hearing and balance and is located in the inner ear near the back of the skull. One part of the eighth cranial nerve transmits sound and the other part sends balance information to the brain from the inner ear. It is one of the 12 cranial nerves that originate in the brainstem.
About 5% of all primary brain tumors are acoustic neuromas.
Causes of and risk factors for acoustic neuroma:
Acoustic neuromas are believed to develop from an overproduction of Schwann cells that press on the hearing and balance nerves in the inner ear. Schwann cells are cells that normally wrap around and support nerve fibers. If the tumor becomes large, it can press on the facial nerve or brain structure. This type of brain tumor usually develops in adults between the ages of 30 and 60.
People with the genetic condition neurofibromatosis 2 often develop acoustic neuromas in both ears. Neurofibromatosis 2 causes tumors on the nerves of the head and spinal cord and can cause brain tumors.
Symptoms of an acoustic neuroma:
The following are the most common symptoms of acoustic neuroma. However, each individual may experience symptoms differently.
When a neuroma develops, it may cause any or all of the following:
- hearing loss
- tinnitus (ringing in the ears)
- paralysis of a facial nerve
- life-threatening problems in the brain
The symptoms of acoustic neurinoma may resemble other conditions or medical problems. Always consult your physician for a diagnosis.