Vestibular schwannoma (acoustic neuroma)

A vestibular schwannoma is a benign tumor on the nerve connecting the ear to the brain. It’s sometimes called an acoustic neuroma, a neurolemmoma or a Schwann cell tumor.

Vestibular schwannoma and genetics

About 95% of vestibular schwannomas occur on only one ear. They occur in people who don’t have a family history of these benign tumors.

When a person has a vestibular schwannoma in both ears, it’s likely to be related to a genetic condition called neurofibromatosis type 2 (NF2). Your doctor may suspect NF2 if a close family member also has NF2 and the acoustic neuroma tumor occurs before age 30. They may also suspect NF2 if the person has had a cataract, glioma tumor or meningioma tumor.

We don’t know what causes vestibular schwannomas. However, almost all of these tumors have mutations related to a gene located on chromosome 22. Researchers continue to look for more information.

Symptoms of a vestibular schwannoma

Vestibular schwannoma symptoms usually appear slowly and the tumors grow slowly over a period of years. However, symptoms can also appear suddenly.

When the tumor is only affecting the part of the vestibular nerve that affects hearing, the symptoms are related to hearing or balance such as ringing or buzzing in one ear (tinnitus), gradual hearing loss in one ear, a feeling of fullness in the ear, and balance problems.

The trigeminal nerve, which controls muscles in the face, is next to the vestibular nerve. When a tumor grows large enough, it may cause pressure on the trigeminal nerve and cause weakness in facial muscles.

Other vestibular schwannoma symptoms are:

• Headaches
• Fatigue
• Changes in thinking
• Oral or swallowing issues

Sometimes these benign tumors grow large enough to put pressure on areas of the brain and may become life-threatening.

Vestibular schwannoma diagnosis

First, you’ll meet with your doctor for a physical exam and to discuss your symptoms. They’ll check some neurological responses like balance and reflexes. Next, your doctor may order ear and eye tests, including:

• Audiogram, a procedure to test the softest sounds you can hear.
• Auditory brainstem response test, which measures the rate of electric impulses traveling from the inner ear to the brainstem. It’s sometimes called an ABR, BAER or BSER.
• Electronystagmography, a test of eye movements to find out how well the nerves are functioning and to gauge balance.

Diagnosis of an acoustic neuroma tumor can be confirmed with imaging tests such as MRI with contrast dye or CT, which produce 3D images of the area. Imaging tests also help your doctor plan surgery to remove the tumor. Vestibular schwannomas that don’t produce symptoms are sometimes discovered accidentally when such imaging tests are done for other reasons.

Treatment options

If you have a vestibular schwannoma diagnosis, your Aurora Health Care team, including neurologists and neurosurgeons, will work with you to find the best treatment based on your test results, age and overall health.

Vestibular schwannoma treatment options may include:

• Watchful waiting
• Microsurgery to remove as much of the tumor as possible
• CyberKnife® radiosurgery, a noninvasive, robotic system that delivers high radiation doses to tumors with pinpoint accuracy
• Rehabilitation for any hearing or balance problems

Brain surgery (craniotomy) may be considered for larger tumors or tumors that cause severe symptoms. Surgery carries a risk of damage to the vestibular or trigeminal nerves that can make symptoms worse. Radiation may be a better option and may be chosen for:

• Elderly people
• People with poor medical health
• People with bilateral tumors
• People whose single tumor affects the only ear in which they have hearing

Watchful waiting may be better for small tumors that grow slowly or aren’t causing symptoms because it avoids the risk of damage to the nerves. If your doctor suggests this approach, you’ll be asked to come in for regular imaging scans to monitor your tumor.