Neurofibrosarcoma

Peripheral nerve sheath tumors, also called neurofibrosarcomas, are malignant tumors that form in the soft tissues surrounding the peripheral nerves, which receive messages from the brain and stimulate voluntary movement. These tumors are usually found in the arms and legs, and can spread extensively along nerve tissue.

If your child has neurofibromatosis (which involves alterations in the NF1 gene), he may be at an increased risk for developing neurofibrosarcoma. These tumors occur in up to 16 percent of people with neurofibromatosis, also known as Recklinghausen's disease. This is a genetic condition in which benign fibrous tumors develop inside nerve tissue.

Children with neurofibromatosis type 1 are at very high risk of developing these tumors. Because they affect tissue that is elastic and easily moved, peripheral nerve sheath tumors may exist for a long time before they are diagnosed.

The most common symptoms include:

• Painless swelling or a lump
• Pain or soreness from compressed nerves or muscles
• Nerve loss
• Limp or difficulty using the arms, legs, feet, or hands

The exact cause of neurofibrosarcoma is not entirely understood, however studies have indicated that genetics may play a role in the formation of all soft tissue sarcomas. Limited studies have shown a possible link between soft tissue sarcomas and other types of cancer.

In addition to a complete physical exam, a doctor may order the following to diagnose a peripheral nerve sheath tumor:

• Biopsy
• X-ray
• Magnetic resonance imaging (MRI)
• Computerized tomography (CT or CAT) scan
• Bone scan or PET scan
• Blood tests, including a complete blood count

After all tests are completed, doctors will be able to outline the best treatment options.

Staging

Once neurofibrosarcoma has been diagnosed, the tumor is given a “stage,” usually stage I, stage II, stage III, or stage IV. This indicates how far the tumor has spread from its original location. The stage helps doctors decide which form of treatment is most appropriate, and predicts how the condition is likely to respond to therapy.

Neurofibrosarcoma may be localized (meaning it has not spread beyond the nerve tissue where it arose) or metastatic (meaning it has spread, in this case usually to the lungs). However, most often, neurofibrosarcoma remains localized.

Surgery to remove the entire tumor and nearby tissue is the standard treatment for peripheral nerve sheath tumors. Depending on the size and location of the tumor, it may be necessary to remove all or part of a limb. In most cases, a limb-sparing procedure is used to avoid amputation. Chemotherapy and radiation therapy may be given before surgery to shrink the tumor or after surgery to kill any remaining cancer cells.

The prognosis is directly related to the size and extension of the tumor and the ability to completely resect it with surgery. The five-year survival rates range from close to 80 percent if the tumor is small and resected, to less than 30 percent if it has spread to other organs.

Patients with peripheral nerve sheath tumors are treated at Dana-Farber/Boston Children's Cancer and Blood Disorders Center through the Bone and Soft Tissue Program.