Neurofibrosarcoma (Peripheral Nerve Sheath Tumor)

What is neurofibrosarcoma?

Peripheral nerves are nerves that receive messages from the central nervous system (brain and spinal cord) leading them to stimulate voluntary movement. Neurofibrosarcoma, also known as peripheral nerve sheath tumor, is a malignant tumor that develops in the cells surrounding these peripheral nerves. It can sometimes arise in patients with neurofibromatosis (NF1). Neurofibrosarcoma is usually found in the arms and legs and can spread extensively along nerve tissue. It usually does not metastasize (spread) to other parts of the body, although it sometimes spreads to the lungs. It affects mostly young and middle age adults. Neurofibrosarcoma is considered a soft tissue sarcoma, cancer that originates in soft tissue which includes fat, muscles, tendons, nerves, synovial tissue, blood vessels and other fibrous tissue. As a group, soft tissue sarcomas account for less than 1 percent of all new cancer cases each year. In the United States, approximately 900 children and adolescents are diagnosed with soft tissue sarcomas each year. Neurofibrosarcoma accounts for 5 to 7 percent of all soft tissue sarcoma cases.

What causes neurofibrosarcoma?

The exact cause of neurofibrosarcoma is not entirely understood, however, studies have indicated that genetic alterations may play a role in the formation of all soft tissue sarcomas. Researchers have studied a small number of families that contain several members of one generation who have developed soft tissue sarcomas. In addition, limited studies have shown a possible link between soft tissue sarcomas and the development of other types of cancer. People with neurofibromatosis (which involves alterations in the NF1 gene) are at an increased risk for developing neurofibrosarcoma. Neurofibromatosis, also known as Recklinghausen's disease, is a genetic condition in which benign fibrous tumors develop inside nerve tissue. Neurofibrosarcoma occurs in up to 16 percent of those with neurofibromatosis.

What are the symptoms of neurofibrosarcoma?

Because neurofibrosarcoma affects tissue that is elastic and easily moved, a tumor may exist for a long time before being discovered, growing large and pushing aside surrounding tissue. The following are the most common symptoms associated with neurofibrosarcoma. However, individuals may experience symptoms differently. The symptoms can vary greatly depending on size, location, and spread of tumor. Symptoms may include: A painless swelling or lump, usually in the arms or legs Pain or soreness Limping or other difficulty using the arms, legs, feet or hands The symptoms of neurofibrosarcoma may resemble other conditions or medical problems. Always consult a physician for a diagnosis.

How is neurofibrosarcoma diagnosed?

In addition to a complete medical history and physical examination, the most conclusive diagnostic procedure for neurofibrosarcoma is a biopsy, a single tissue sample taken from the tumor through a simple surgical procedure. The tumor's cellular appearance under a microscope enables doctors to distinguish it from other types of cancer and determine how aggressive the cancer is. Patients undergo various imaging studies that will include one or more of the following: X-rays - a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film X-rays are often the first diagnostic study, and often give the doctor information regarding the need for further testing. Magnetic Resonance Imaging (MRI) - a diagnostic procedure that uses a combination of large magnets, radiofrequencies and a computer to produce detailed images of organs and structures within the body. This test is done to judge the extent and size of the tumor and its relationship to adjacent nerves, blood vessels and bone. Computerized Tomography scan (also called CT or CAT scan) - a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices)both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat and organs. CT scans are more detailed that general X-rays Bone scans - a nuclear imaging method to evaluate any degenerative and/or arthritic changes in the joints; to detect bone diseases and tumors; to determine the cause of bone pain or inflammation. This test is to rule out any infection or fractures. Other tests include Complete blood count (CBC) - a measurement of size, number and maturity of different blood cells in a specific volume of blood Blood tests - (including blood chemistries)

Staging

Once neurofibrosarcoma has been diagnosed, the tumor is staged. This process indicates how far the tumor has spread from its original location. The stage of a tumor suggests which form of treatment is most appropriate, and predicts how the condition will probably 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.

Treatment

Specific treatment for neurofibrosarcoma will be determined by your child's (or your) physician based on: The patient's age, overall health, and medical history Extent of the disease The patient's tolerance for specific medications, procedures or therapies How the doctor expects the disease may progress Your opinion and preference

Treatment is primarily surgical excision, but may include some combination of the following:

Surgery Surgery includes biopsy and surgical removal of the entire tumor, and nearby tissue. Depending on the location and size of the tumor, it may be necessary to remove all or part of the limb. In most cases limb-sparing surgery is used to avoid amputation. The following is a description of both procedures. Limb-salvage surgery: Limb-sparing surgery is indicated only if the orthopaedic surgeon determines that it is possible that the tumor, and wide margins of healthy tissue surrounding the tumor, can be removed. Through limb-sparing surgery, all of the tissue involved with the tumor, including some degree of nerve and other tissue surrounding it are removed, unaffected tendons, nerves and vessels are saved. If bone is also removed, it is usually replaced with a bone graft or with a metal rod. Subsequent surgery may be needed to repair or replace rods, which can become loose or break. Patients who have undergone limb-salvage surgery need intensive rehabilitation. It may take as long as a year for a patient to regain full use of a leg following limb-salvage surgery. Some patients who have limb-sparing procedures may eventually have to undergo amputation. Radiation therapy and/or chemotherapy are given either before surgery to shrink the tumor, or after surgery to kill remaining cancer cells. Amputation: In certain cases, your orthopaedic surgeon determines that the tumor cannot be removed because, for example, it involves the nerves and blood vessels, amputation is the only option. During the operation, doctors ensure that muscles and skin form a cuff around the amputated bone. A cast is applied in the operating room which permits a temporary artificial leg (prosthesis) to be applied during the first few post-operative days for walking. Crutches are used for several weeks. As the swelling decreases (10 to 14 days) the patient is fitted for a plastic, temporary socket and prosthesis, which is used for 3 to 4 months until the stump is healed sufficiently to accept a permanent artificial leg. The advantages of an amputation are that it is a simple operation with minimal chances of surgical complication and it definitively removes the local tumor. The functional outcome is good with the modern prostheses available today and with "immediate-fit" prostheses applied in the operating room. Although the patient will probably have a limp with above-the-knee amputations, the procedure is functional and stable. He/she will be able to walk, climb stairs, swim (with the prosthesis on or off) and participate in many sports such as skiing, basketball, baseball, and tennis although running will be limited. The functional limitations are left to the imagination and determination of the patient.