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Schwannoma

Schwannoma Overview

A schwannoma is a rare type of tumor that develops from cells called Schwann cells. These cells are responsible for creating a protective covering around the peripheral nerves in your body, but can form tumors when their growth becomes uncontrolled.

Much like electrical wires, nerves carry electrical signals throughout your body. Schwann cells lay down a fatty substance called myelin that functions like the insulation around an electrical wire. Schwannomas usually grow slowly and are usually noncancerous (benign). However, in rare cases, they can be cancerous (malignant).

Schwannomas typically affect only a single nerve. As the tumor grows and compresses the nearby nerve it can cause symptoms that depend on the location and function of the nerve. These symptoms can include pain, numbness, tingling, weakness, or even loss of muscle function. Vestibular schwannomas (also called acoustic neuromas) are the most common type of schwannoma and affect the nerves that connect your inner ear to your brain.

Illustration of a schwannoma on a nerve root near the spine
This illustration shows a nerve root schwannoma near the thoracic region of the spine.

Schwannomas only occur on the nerves of the peripheral nervous system, or outside of the brain and spinal cord (the central nervous system). Oligodendrocytes, another kind of cell, are responsible for myelin formation in the central nervous system.

The exact cause of Schwannomas is not fully understood, but they can sometimes be associated with a genetic conditions called neurofibromatosis type 2 (NF2) and schwannomatosis.

Most schwannomas can be treated and cured through surgery. However, depending on the size and location of the tumor, there may be a risk of nerve damage during the surgery.

Schwannoma Symptoms

The symptoms of a schwannoma can vary depending on its size, location, and the nerve it affects. They can include:

  • Pain in the area where the tumor is located. The pain may be constant or intermittent, but not all schwannomas cause pain.
  • Numbness and tingling sensations in the affected area. This can occur in the limbs, face, or other parts of the body depending on the nerve involved.
  • Muscle weakness that can affect movement and may cause difficulty in performing everyday tasks.
  • Loss of sensation in the area supplied by the affected nerve
  • Changes in reflexes
  • A visible or palpable lump may develop at the site of the schwannoma, especially if the tumor is near the skin.

Keep in mind that a schwannoma cannot be diagnosed based on symptoms alone, and other conditions may have similar symptoms. Only a medical professional can provide you with a definitive diagnosis.

Schwannoma Treatments

The primary treatment for schwannomas is surgical removal of the tumor. The goal of the surgery is to completely excise the tumor while preserving the function of the affected nerve as much as possible.

Some tumors, particularly small and superficial Schwannomas, can be removed without disturbing the surrounding nerve tissue.

If your schwannoma is larger or deeply embedded, more extensive surgery may be required. This could involve removing a portion of the nerve or, in rare cases, complete removal of the affected nerve. Removing the entire nerve may result in permanent loss of sensation or function in the area supplied by that nerve.

illustration showing a vestibular schwannoma
Illustration showing a vestibular schwannoma, also known as an acoustic neuroma.

In situations where complete removal of the tumor is not feasible due to its size or location, or if you are not a suitable candidate for surgery, other treatment options may be considered. These options include:

  • Observation: If your Schwannoma is small, slow-growing, and not causing significant symptoms, your doctor may recommend regular monitoring through imaging tests (such as MRI) to observe any changes in the tumor over time.
  • Radiation therapy: In some cases, radiation therapy may be used to shrink the tumor or prevent its growth. This treatment option is typically reserved for patients who are unable to undergo surgery or for tumors that have recurred after surgery.
  • Medications: Certain medications, such as pain relievers or corticosteroids, may be prescribed to manage pain or inflammation associated with the tumor.

The treatment approach will depend on several factors, including the size and location of the tumor, the severity of symptoms, and your overall health.

Additional Information on Schwannoma

How common are schwannomas?

Schwannomas are rare, with less than 200,000 diagnosed annually in the United States. However, they are the most common tumor of the peripheral nerve in adults.

Who gets schwannomas?

Schwannomas can affect anyone at any age. They are more common in people with the genetic disorders neurofibromatosis type 2 (NF2) and schwannomatosis.

How are schwannomas diagnosed?

The presence of a tumor can be ascertained by diagnostic imaging—usually computed tomography (CT) or magnetic resonance imaging (MRI). Your doctor may suspect a schwannoma based on imaging alone, but a biopsy will be required to provide you with a definitive diagnosis.

Group 49
  Tumors Diagnosed
Less than 200,000 schwannomas are diagnosed annually in the United States

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Medically Reviewed by Igor Barani, MD on July 14, 2023