Schwannoma

A schwannoma is a tumor that develops from the Schwann cells in your peripheral nervous system or nerve roots. Schwannomas are almost always benign (noncancerous) but can sometimes be malignant (cancerous). They’re usually slow-growing.

Schwann cells assist the conduction of nerve impulses. They wrap around peripheral nerves and provide protection and support. Your peripheral nervous system includes nerves that travel from your spinal cord and brain to carry signals to and from the rest of your body.

A common area for schwannomas is in the nerve that connects your brain to your inner ear (vestibular schwannoma). Cancerous schwannomas most frequently affect the sciatic nerve of your leg, the brachial plexus nerves in your arm and the group of nerves in your lower back called the sacral plexus.

Schwannomas are sometimes called neurilemmomas or neuromas. If a schwannoma is malignant, it may be referred to as a soft tissue sarcoma.

Schwannomas are solitary in 90% of cases, meaning there’s only one tumor.

What is a vestibular schwannoma?

A vestibular schwannoma, also known as acoustic neuroma, is a type of schwannoma that develops from the balance and hearing nerves supplying your inner ear. It’s usually benign (noncancerous) and slow-growing.

But as the tumor grows, it affects the hearing and balance nerves, usually causing hearing loss in the affected ear, tinnitus (ringing in your ear) and dizziness.

Is schwannoma a brain tumor?

It can be, but not always. A schwannoma can form in your brain or head, but it can also form elsewhere in your body. This is because schwannomas develop from cells (Schwann cells) in your peripheral nervous system, which consists of nerves in your brain and throughout your body.

The most common type of schwannoma, vestibular schwannoma, is considered a brain tumor.

Who do schwannomas affect?

Schwannomas most commonly affect people between the ages of 50 and 60 years. They rarely occur in children.

Schwannomas usually develop randomly in otherwise healthy people. In some cases, a schwannoma is caused by a genetic condition, such as neurofibromatosis 2 (NF2), schwannomatosis or Carney complex. People with these genetic conditions usually have more than one schwannoma.

How common are schwannomas?

Schwannomas are rare. They affect fewer than 200,000 people each year in the United States. About 60% of benign schwannomas are vestibular schwannomas (acoustic neuromas).