A vestibular schwannoma is a benign tumor that develops from the nerves associated with balance and hearing that supply the inner ear. The condition can affect one or both ears and is usually characterized by symptoms such as loss of balance, ringing in the ears, and headaches. Treatment options may include surgery, radiation therapy, and watchful waiting.
What Is a Vestibular Schwannoma?
A vestibular schwannoma is a benign, usually slow-growing tumor that develops from the nerves associated with balance and hearing that supply the inner ear. The condition results from an overproduction of Schwann cells -- the cells that normally wrap around nerve fibers like the skin of an onion to help support and insulate the nerves.
Other names for a vestibular schwannoma include:
- Acoustic neuroma
- Acoustic neurinoma
- Acoustic neurilemoma.
Unilateral Versus Bilateral
A vestibular schwannoma can affect one or both ears. When one ear is affected, it's known as unilateral vestibular schwannoma. When both ears are affected, it's known as bilateral vestibular schwannoma.
Unilateral Vestibular Schwannoma
This condition affects only one ear. It accounts for approximately 8 percent of all tumors inside the skull. One out of every 100,000 individuals per year develops a vestibular schwannoma. Symptoms may develop at any age, but usually appear between the ages of 30 and 60. This is not a hereditary condition.
Bilateral Vestibular Schwannoma
Bilateral vestibular schwannomas affect both hearing nerves and are usually associated with a genetic disorder called neurofibromatosis type 2 (NF2). Half of affected individuals have inherited the disorder from an affected parent, and half seem to have a mutation for the first time in their family. Each child of an affected parent has a 50 percent chance of inheriting the condition.
Unlike people with a unilateral vestibular schwannoma, individuals with NF2 usually develop symptoms of vestibular schwannoma in their teens or early adulthood. In addition, people with NF2 usually develop multiple brain- and spinal cord-related tumors. They can also develop tumors of the nerves associated with:
- Eye and facial movement
- Facial sensation.
Determining the best way to manage bilateral vestibular schwannomas as well as the additional nerve, brain, and spinal cord tumors is more complicated than deciding how to treat a unilateral vestibular schwannoma. Further research is needed to determine the best treatment for individuals with neurofibromatosis type 2.
(Click Acoustic Neuroma Gene for more information on the gene responsible for neurofibromatosis type 2.)