Malignant peripheral nerve sheath tumors are a rare form of sarcoma that forms in the protective linings surrounded the major nerves of the body. This is an aggressive form of cancer that is hard to treat due to the location of the tumors making surgery difficult and limited how much medication reaches the affected area.
While many tumors that form in the nervous system are benign, these tumors are malignant and will continue to grow and spread without treatment. Most cases are caused by a genetic disorder, radiation exposure, or unknown triggers.
Since the tumors are hidden deep in the peripheral nerves, there are often no early symptoms. As the tumors grow and press on the nerves, patients begin to notice pain and numbness in the affected area.
The peripheral nerves connect to the limbs, so pain can be felt almost anywhere in the limbs or torso. Some patients notice a palpable mass in their muscle tissue, or develop weakness and dizziness due to nerve compression.
Approximately 5-10% of all soft tissue sarcomas are malignant peripheral nerve sheath tumors (MPNST) and they can occur independently or can be prompted by neurofibromatosis-1 (NF1). The direct causes of MPNSTs are currently unknown and further research is needed to determine the etiology of these tumors, but the incidence of MPNSTs are much higher in patients who have received radiation therapy.
Studies have revealed that 50% of all malignant peripheral nerve sheath tumors occur in patients suffering from NF1. This suggests a pre-existing neurofibroma significantly increases the risk that one will develop a MPNST. Transversal studies have found a 1-2% higher occurrence of MPNST among all NF1 patients, but, as time goes on, the risk probability increases. NF1 patients have an overall 10% chance of developing malignant peripheral nerve sheath tumors in their lifetimes.
Generally, adults between the ages of 20 and 50 have the highest chance of contracting a MPNST, but children are also susceptible to contracting these types of soft tissue tumors. 10 to 20% of all MPNST cases involve patients between the ages of 11 months and 20 years old.
Since this form of cancer is hard to treat and aggressive, patients need multiple specialists working together on their case. Oncologists with specific training and experience in sarcoma management plan out surgeries to remove as much of the tumor or tumors as possible, following with chemotherapy to target any remaining material.
Nerve and pain specialists help limit damage to the body’s functions and assist the patient in recovering. Genetic testing and therapy can also help the patient determine what caused the cancer to form and what other complications may arise due to their genetic makeup. Relapse rates are high with this form of sarcoma, so ongoing monitoring is necessary for the rest of the patient’s life.
Current research has not yet identified ways of preventing malignant peripheral nerve sheath tumors and patients who have previously had a MPNST should be diligent in getting tested frequently. Regular doctor visits with blood tests, scans, and physical examinations should be conducted in an effort to find tumors as early as possible. Through the first several years, since the initial diagnosis, there is a high metastasizing potential and possibility of recurrence, making early detection vital.
Treatment of malignant peripheral nerve sheath tumors can involve surgery or radiotherapy, or, in some cases, a combination of both treatments. Chemotherapy is another option that one’s doctor may consider, depending on the location and stage of the tumor. There are also opportunities to participate in clinical trials for drugs that may either cure, treat, or prevent MPNSTs from occurring.