What is Schwannomatosis?

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Schwannomatosis is a rare type of neurofibromatosis (NF). Only one in 40,000 people have this disorder, but some scientists think it may be under-diagnosed. It causes multiple tumors called schwannomas to grow along nerve sheaths (the coverings of nerves). Schwannomatosis can cause severe pain and neurological dysfunction. Schwannomatosis was identified as genetically and clinically distinct from other forms of NF (NF 1 and NF 2) in 1997.

Symptoms of Schwannomatosis

Pain may be the first symptom that causes a patient with Schwannomatosis to see a doctor. When schwannomas grow and press on nerves or other body tissue, the result can be intense pain. Patients may have pain anywhere on the body and sometimes in multiple areas. Identifying the cause of the pain can be difficult. (For example, a tumor pressing on a nerve in the neck may cause pain or tingling in the arm.) Symptoms depend on where the tumors grow and what body parts they press on, including the spinal cord. Schwannomatosis symptoms may include:

• Headaches
• Numbness
• Tingling
• Vision problems
• Facial weakness
• Bowel or bladder dysfunction
• Weakness
• Swollen areas and lumps

Some patients have Schwannomatosis I n just one area of their body. This form is called mosaic or segmental Schwannomatosis.

What Causes Schwannomatosis?

Half of the patients with Schwannomatosis have mutations in genes SMARCB1 or LZTR1. The mutations could be inherited, but they most often occur in people that do not have a family history of the disorder (sporadic Schwannomatosis). Only 15% of patients have the inherited form (familial Schwannomatosis). Medical researchers are trying to identify other gene mutations that could cause Schwannomatosis.

Schwannomatosis Diagnosis and Genetic Testing

The partial list of symptoms noted above can have many other causes. Seeing an expert and getting an accurate diagnosis is an essential first step to treatment. The three main types of NF (NF 1, NF 2 and Schwannomatosis) have multiple overlapping symptoms. Misdiagnosis can delay proper care and impact reimbursement from your health insurance provider. A specialist has the additional training needed to rule out other similar diseases and recognize the symptoms typical of each form of NF.

The first step toward a diagnosis is usually a magnetic resonance imaging (MRI) scan and a tumor biopsy. A specialist uses the following diagnostic criteria and other indicators to confirm Schwannomatosis:

• Age 30 or over
• Two or more schwannomas located somewhere other than the skin
• Tumor type confirmed with a tissue sample examined under a microscope
• No tumor in the vestibule of the inner ear, as shown in an MRI scan
• No genetic or physical signs of NF Type 2
• The patient does not have a relative with NF 2
• A first-degree relative with Schwannomatosis plus one nonvestibular schwannoma confirmed by a pathologist
• No evidence of dysfunction on the eighth cranial nerve

Genetic testing for Schwannomatosis is complex and may not provide a definitive answer. Not all genes are tested, and the mutated gene may not be detected in the sample, especially for mosaic Schwannomatosis. Patients may need to speak with a genetic counselor for more in-depth information.

About Schwannoma Tumors: Schwannoma Neurofibroma

Patients with neurofibromatosis may have neurofibroma tumors or schwannoma tumors. The tumors are comprised of different cell types and require specific treatments. Doctors can view the differences between these tumors and others by analyzing cell samples under a microscope.

A schwannoma is a tumor composed of Schwann cells. These cells create the lining around nerves. A patient can have one tumor or many; however, Schwannomatosis is associated with multiple tumors. Some schwannoma tumors do not cause symptoms or pain. It is vital to have schwannomas regularly observed by a specialist to check for changes or growth. Although they are typically benign, approximately 5% of these tumors become malignant (cancerous).

Schwannomatosis and Neurofibromatosis Pain

Schwannomatosis patients can have spinal or peripheral nerve schwannomas that cause intense pain. Some of these tumors are difficult to treat or entirely remove, and patients may suffer from depression and anxiety due to chronic pain or lifestyle changes. It is critical to proactively image tumors to manage them before they get too large, invasive or inoperable. Imaging may also indicate other causes of pain, such as herniated discs or arthritis. Neurofibromatosis pain is managed in several ways, including:

• Removing tumors
• Medications
• Spinal block

Schwannomatosis Treatment

Regular follow-up visits to observe changes in tumors or new symptoms are essential. Management of the disorder is individualized for each patient and their concerns. Sometimes, tumors can be removed with surgery or electrodesiccation. Tumor removal is best performed by a highly experienced NF surgical specialist. When removed completely, 95% of tumors will not return. Those that do recur may take years to cause symptoms.

There is no cure for Schwannomatosis at this time, but research and tissue sample collection for research is ongoing. Dr. Weinberg can help you get involved in research studies or help you find additional information or specialists for Schwannomatosis. Please get in touch with our office to schedule a consultation. Our caring and knowledgeable staff will be happy to speak with you.