A vestibular schwannoma (VS) is a benign primary intracranial tumor of the myelin-forming cells of the vestibulocochlear nerve (8th cranial nerve).
A type of schwannoma, this tumor arises from the Schwann cells responsible for the myelin sheath that helps keep peripheral nerves insulated.Although it is also called an acoustic neuroma, this is a misnomer for two reasons. First, the tumor usually arises from the vestibular division of the vestibulocochlear nerve, rather than the cochlear division.Second, it is derived from the Schwann cells of the associated nerve, rather than the actual neurons (neuromas).
Approximately 2,000 to 3,000 cases are diagnosed each year in the United States (6 to 9 per million persons). Comprehensive studies from Denmark published in 2012 showed an annual incidence of 19-23 per million from 2002 to 2008, and over the last 30 year.
the reported incidence has been increasing, until the last decade in which an approximation of the true incidence may have been found.Most recent publications suggest that the incidence of vestibular schwannomas has been rising because of advances in MRI scanning.
Most cases are diagnosed in people between the ages of 30 and 60, and men and women appear to be affected equally. Most vestibular schwannomas occur spontaneously in those without a family history. One confirmed risk factor is a rare genetic mutation called NF2.
The primary symptoms of vestibular schwannoma are unexplained progressive unilateral hearing loss and tinnitus and vestibular (disequilibrium) symptoms. Treatment of the condition is by surgery or radiation and often results in substantial or complete hearing loss in the affected ear. Observation (non-treatment) over time also usually results in hearing loss in the affected ear.