Schwannomatosis

Schwannomatosis is one form of a genetic disorder called Neurofibromatosis (NF) that has only recently been recognized. It is a rare disorder, affecting only around 1:40,000 individuals.

Symptoms

• Schwannomas occur instead of Neurofibromas.
• Multiple Schwannomas occur.
• The Schwannomas develop on cranial, spinal and peripheral nerves.
• Chronic pain, and sometimes numbness, tingling and weakness.
• About 1/3 of patients have segmental Schwannomatosis, which means that the Schwannomas are limited to a single part of the body, such as an arm, a leg or the spine.
• There are several cases where people with Schwannomatosis have developed a vestibular Schwannoma (acoustic neuroma).
• Patients with Schwannomatosis do not have learning disabilities related to the disease.
• Symptoms are generally brought on by hormonal changes such as puberty and pregnancy.

Cause

• Like the NF1 and NF2 genes, the candidate Schwannomatosis gene, named INI1, is a tumor suppressor that regulates cell cycle, growth and differentiation. INI1 is also known as SMARCB1, hSNF5, or BAF47, and lies on human Chromosome 22. INI1 is also mutated in other tumors including malignant brain & kidney tumors in infants.
• Schwannomatosis is known to be a genetic disorder, however it can skip generations.

Treatment

• If feasible, the Schwannomas can be surgically removed. Any tumor-associated pain usually subsides after tumor removal. Damaged nerves and scar tissue can be a result of surgery and pain can be an ongoing problem.
• Sometimes, a tumor will reappear at the same site after surgery.
• If surgery is unfeasible, then pain management will have to be used. Schwannomatosis can sometimes cause severe, untreatable pain over time.
• Other than surgery and/or pain management, there are no other medical treatments available. There are no drugs available to treat Schwannomatosis.
• Gamma knife surgery can be performed on head tumors to help slow growth of a tumor, although there is no guarantee that it will work.
• Recently, many advances are being made in the treatment of schwannomas. Of interest is CyberKnife, manufactured by Accuray. Success rates, although limited in data, appear to be in the low to mid ninety percent range.