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U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES ∙ National Institutes of Health

NIDCD Fact Sheet | Hearing and Balance

Vestibular Schwannoma (Acoustic 

Neuroma) and Neurofibromatosis 

What is a vestibular 

schwannoma (acoustic 

neuroma)?

A vestibular schwannoma (also known as 

acoustic neuroma, acoustic neurinoma, or 

acoustic neurilemoma) is a benign, usually 

slow-growing tumor that develops from 

the balance and hearing nerves supplying 

the inner ear. The tumor comes from an 

overproduction of Schwann cells—the cells 

that normally wrap around nerve fibers like 

onion skin to help support and insulate nerves. 

As the vestibular schwannoma grows, it 

affects the hearing and balance nerves, usually 

causing unilateral (one-sided) or asymmetric 

hearing loss, tinnitus (ringing in the ear), 

and dizziness/loss of balance. As the tumor 

grows, it can interfere with the face sensation 

nerve (the trigeminal nerve), causing facial 

numbness. Vestibular schwannomas can also 

affect the facial nerve (for the muscles of the 

face) causing facial weakness or paralysis on 

the side of the tumor. If the tumor becomes 

large, it will eventually press against nearby 

brain structures (such as the brainstem and the 

cerebellum), becoming life-threatening.

Source: NIH/NIDCD

Inner ear with vestibular schwannoma (tumor)

A vestibular schwannoma (also known as acoustic neuroma, 

acoustic neurinoma, or acoustic neurilemoma) is a benign, 

usually slow-growing tumor that develops from the balance and 

hearing nerves supplying the inner ear.
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How is a vestibular schwannoma 

diagnosed?

Unilateral/asymmetric hearing loss and/or tinnitus and 

loss of balance/dizziness are early signs of a vestibular 

schwannoma. Unfortunately, early detection of the 

tumor is sometimes difficult because the symptoms 

may be subtle and may not appear in the beginning 

stages of growth. Also, hearing loss, dizziness, and 

tinnitus are common symptoms of many middle and 

inner ear problems (the important point here is that 

unilateral or asymmetric symptoms are the worrisome 

ones). Once the symptoms appear, a thorough ear 

examination and hearing and balance testing (audiogram, 

electronystagmography, auditory brainstem responses) 

are essential for proper diagnosis. Magnetic resonance 

imaging (MRI) scans are critical in the early detection of 

a vestibular schwannoma and are helpful in determining 

the location and size of a tumor and in planning its 

microsurgical removal.

How is a vestibular schwannoma 

treated?

Early diagnosis of a vestibular schwannoma is key to 

preventing its serious consequences. There are three 

options for managing a vestibular schwannoma: (1) 

surgical removal, (2) radiation, and (3) observation. 

Sometimes, the tumor is surgically removed (excised). The 

exact type of operation done depends on the size of the 

tumor and the level of hearing in the affected ear. If the 

tumor is small, hearing may be saved and accompanying 

symptoms may improve by removing it to prevent its 

eventual effect on the hearing nerve. As the tumor grows 

larger, surgical removal is more complicated because the 

tumor may have damaged the nerves that control facial 

movement, hearing, and balance and may also have 

affected other nerves and structures of the brain.

The removal of tumors affecting the hearing, balance, or 

facial nerves can sometimes make the patient’s symptoms 

worse because these nerves may be injured during 

tumor removal.

As an alternative to conventional surgical techniques, 

radiosurgery (that is, radiation therapy—the “gamma 

knife” or LINAC) may be used to reduce the size or limit 

the growth of the tumor. Radiation therapy is sometimes 

the preferred option for elderly patients, patients in 

poor medical health, patients with bilateral vestibular 

schwannoma (tumor affecting both ears), or patients 

whose tumor is affecting their only hearing ear. When 

the tumor is small and not growing, it may be reasonable 

to “watch” the tumor for growth. MRI scans are used to 

carefully monitor the tumor for any growth.

What is the difference between 

unilateral and bilateral vestibular 

schwannomas?

Unilateral vestibular schwannomas affect only one ear. 

They account for approximately 8 percent of all tumors 

inside the skull; approximately one out of every 100,000 

individuals per year develops a vestibular schwannoma. 

Symptoms may develop at any age but usually occur 

between the ages of 30 and 60 years. Most unilateral 

vestibular schwannomas are not hereditary and 

occur sporadically.

Approximately one out of 

every 100,000 individuals 

per year develops a 

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 
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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 disorder. Unlike those 

with a unilateral vestibular schwannoma, individuals 

with NF2 usually develop symptoms in their teens or 

early adulthood. In addition, patients with NF2 usually 

develop multiple brain and spinal cord related tumors. 

They also can develop tumors of the nerves important 

for swallowing, speech, eye and facial movement, and 

facial sensation. Determining the best management of the 

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 NF2.

Scientists believe that both unilateral and bilateral 

vestibular schwannomas form following the loss of the 

function of a gene on chromosome 22. (A gene is a small 

section of DNA responsible for a particular characteristic 

like hair color or skin tone). Scientists believe that this 

particular gene on chromosome 22 produces a protein 

that controls the growth of Schwann cells. When this 

gene malfunctions, Schwann cell growth is uncontrolled, 

resulting in a tumor. Scientists also think that this gene 

may help control the growth of other types of tumors. 

In NF2 patients, the faulty gene on chromosome 22 

is inherited. For individuals with unilateral vestibular 

schwannoma, however, some scientists hypothesize that 

this gene somehow loses its ability to function properly.

There are three options 

for managing a vestibular 

schwannoma: (1) surgical 

removal, (2) radiation, and 

(3) observation.

What is being done about vestibular 

schwannoma?

Scientists continue studying the molecular pathways 

that control normal Schwann cell development to 

better identify gene mutations that result in vestibular 

schwannomas. Scientists are working to better 

understand how the gene works so they can begin to 

develop new therapies to control the overproduction 

of Schwann cells in individuals with vestibular 

schwannoma. Learning more about the way genes help 

control Schwann cell growth may help prevent other 

brain tumors. In addition, scientists are developing 

robotic technology to assist physicians with acoustic 

neuroma surgery. 
Where can I find more information 

about vestibular schwannomas? 

The NIDCD maintains a directory of organizations that 

provide information on the normal and disordered 

processes of hearing, balance, taste, smell, voice, 

speech, and language. Visit the NIDCD website at 

http://www.nidcd.nih.gov to search the directory. 

Use the following keywords to help you find 

organizations that can answer questions and 

provide information on vestibular schwannomas and 

neurofibromatosis:

} Acoustic neuroma 

} Genetic diseases/disorders

} Neurofibromatosis

More NIDCD fact sheets on Hearing and Balance:

} Balance Disorders

} Hearing Loss and Older Adults

} Sudden Deafness

Visit the NIDCD website at http://www.nidcd.nih.gov

to read, print, or download fact sheets. Vestibular Schwannoma 

(Acoustic Neuroma) and 

Neurofibromatosis

NIH Pub. No. 99-580 

November 2015 

For more information, additional addresses and phone 

numbers, or a printed list of organizations, contact us at:

NIDCD Information Clearinghouse

1 Communication Avenue 

Bethesda, MD 20892-3456 

Toll-free Voice: (800) 241-1044 

Toll-free TTY: (800) 241-1055 

Fax: (301) 770-8977 

Email: nidcdinfo@nidcd.nih.gov

http://www.nidcd.nih.gov

 Follow the NIDCD on Twitter at @NIDCD

The NIDCD supports and conducts research and 

research training on the normal and disordered 

processes of hearing, balance, taste, smell, voice, 

speech, and language and provides health information, 

based upon scientific discovery, to the public.

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