Unraveling the Enigma: Understanding Schwannoma and Its Impact on Nerves

A schwannoma is a type of tumor that develops from Schwann cells in a person’s peripheral nervous system or nerve roots. It is sometimes also called a neuroma. 

Schwann cells assist the conduction of nerve signals. They wrap around peripheral nerves and provide protection and support. The body’s peripheral nervous system includes nerves that travel from your spinal cord and brain to carry signals to and from the rest of your body. Schwannomas can often appear in nerves that enable sensations and motion within the arms, legs, face and eyes or skin. Schwannomas are rare, affecting fewer than 200,000 people each year in the United States.

Causes of Schwannomas

Solitary schwannomas are the most common kind, and most appear for unknown reasons. However, certain genetic mutations can cause conditions such as schwannomatosis and Carney complex, both of which are associated with multiple schwannomas. A person can inherit a tendency to form schwannomas from a parent, and can pass the genetic condition to his or her children.

Schwannoma Symptoms and Types

Schwannomas grow slowly and may exist for years without any symptoms. As schwannomas can form in several different areas of your body, the symptoms may vary greatly. Schwannomas can also cause many different symptoms based on where they are located. Some people may have more symptoms than others, and the symptoms can range from mild to severe cases.

Fortunately, most schwannomas are benign (non-cancerous.) However, in about 5% of cases, a schwannoma can become malignant and become a cancerous soft tissue sarcoma or malignant nerve sheath tumor.

One common type of schwannoma is a vestibular schwannoma that grows on the nerves connecting the brain and the inner ear. These schwannomas are usually benign and are almost always present in people with neurofibromatosis type 2. They can cause difficulties with hearing and balance

Diagnosis of Schwannomas

Schwannomas can cause problems similar to those caused by other, more common conditions, and diagnosing a schwannoma without tests can be challenging. You may have a schwannoma for several years before getting diagnosed, as they grow slowly and often cause no symptoms at first.

Based on your description of your symptoms and an examination, your doctor may recommend imaging scans such as a magnetic resonance imaging (MRI), computerized tomography (CT), an ultrasound or an X-ray. Sometimes, a doctor may also find a schwannoma accidentally when reviewing imaging test results you had for another medical reason.

If a tumor appears on one of the scans, your doctor may also perform a biopsy to check if the tumor is schwannoma. This involves taking a small sample from the tumor with a needle. A pathologist will then study cells from the sample under a microscope and perform other tests to see what kind of tumor it is.

Impact of Schwannomas on nerves

Schwannomas that grow on a nerve in an arm or leg can cause pain, weakness, tingling, “pins and needles” sensations, and carpal tunnel syndrome or tarsal tunnel syndrome.

Schwannomas can also affect nerves in the face and neck, resulting in facial muscle pain or paralysis, problems swallowing or moving an eye, and loss of the sense of taste. As they grow, schwannomas can become visually apparent and cause cosmetic concerns.

When a schwannoma grows on a spinal nerve root (where the nerve exists the spinal cord), it can cause symptoms similar to those associated with spinal problems such as a herniated disc. Large nerve root schwannomas within the neck or spine region will often cause tingling or numbness and weakness along the length of the attached nerves, as well as severe pain, impaired nerve function (including bowel or bladder dysfunction) and even paralysis.

Treatment for Schwannomas

A Schwannoma treatment plan primarily depends on where the tumor is located within the body and whether it is causing pain or growing quickly. The most common treatment options include:

• Observation/Monitoring. If the tumor is benign, growing very slowly and you’re experiencing no or very mild symptoms, your healthcare provider may recommend closely monitoring it instead of treating it. If it eventually grows larger and/or causes symptoms, they’ll likely recommend medical treatment for it.
• Surgery. If the tumor is growing more quickly or causing other problems, your healthcare provider may recommend removing it with surgery. While the goal is usually to completely remove the tumor, the surgeon may only be able to remove part of it. As schwannomas form in the sheath surrounding the nerve, the surgery can often be completed without any damage to the nerve.
• Radiation therapy. Radiation therapy is used to help control the tumor growth and improve your symptoms. It may be used in combination with surgery.
• Stereotactic radiosurgery. If the tumor is near blood vessels or vital nerves, a technique called stereotactic radiosurgery may be used to limit damage to healthy tissue. With this technique, doctors deliver radiation precisely to a tumor without making an incision.

While finding out you have a tumor can be frightening, the good news is that schwannomas are almost always benign and slow-growing. If you, or a loved one, has been recently diagnosed with schwannoma, or have developed new or worsening symptoms, talk to our physicians to learn more about treatment options for brain and spinal tumors.