Malignant peripheral nerve sheath tumors are a rare type of cancer that occurs in the lining of the nerves that extend from the spinal cord into the body. Malignant peripheral nerve sheath tumors used to be called neurofibrosarcomas.
Malignant peripheral nerve sheath tumors can occur anywhere in the body, but most often occur in the deep tissue of the arms, legs and trunk. They tend to cause pain and weakness in the affected area and may also cause a growing lump or mass.
Malignant peripheral nerve sheath tumors are typically treated with surgery. In certain cases, radiation therapy and chemotherapy also may be recommended.
Signs and symptoms of malignant peripheral nerve sheath tumors include:
- Pain in the affected area
- Weakness when trying to move the affected body part
- A growing lump of tissue under the skin
When to see a doctor
Make an appointment with your doctor if you have any persistent signs and symptoms that worry you. Malignant peripheral nerve sheath tumors are rare, so your doctor may investigate more-common causes for your symptoms.
It's not clear what causes most malignant peripheral nerve sheath tumors.
Doctors know that these cancers begin when a cell in the protective lining around a nerve develops an error (mutation) in its DNA. The mutation tells the cell to multiply rapidly and to continue living when other cells would normally die. The accumulating cells form a tumor that can grow to invade nearby tissue or spread to other areas of the body.
Factors that increase the risk of malignant peripheral nerve sheath tumors include:
- Previous radiation therapy for cancer. A malignant peripheral nerve sheath tumor may develop in the area treated with radiation 10 to 20 years after treatment.
- Noncancerous nerve tumors. Malignant peripheral nerve sheath tumors can develop from noncancerous (benign) nerve tumors, such as neurofibroma.
- An inherited condition that increases risk of nerve tumors. Malignant peripheral nerve sheath tumors occur more frequently in people with neurofibromatosis 1.
Tests and procedures used to diagnose malignant peripheral nerve sheath tumors include:
- Neurological examination. A detailed, comprehensive neurological examination helps your doctor understand your symptoms and gather clues about your diagnosis.
- Imaging tests. Imaging tests help doctors understand the size of a tumor and look for signs that cancer has spread to other areas of the body. Imaging tests may include an MRI, magnetic resonance neurography, CT and positron emission tomography (PET).
- Removing a sample of tissue for testing (biopsy). A biopsy sample may be obtained by a radiologist before surgery or by a surgeon during surgery. The tissue is sent to a laboratory for specialized testing. The information gathered in the lab may help your doctor better understand your prognosis and your treatment options.
Treatment for malignant peripheral nerve sheath tumors often involves:
Surgery. The goal of surgery is to remove the entire tumor and a small margin of healthy tissue that surrounds it. When that isn't possible, surgeons remove as much of the tumor as they can.
Depending on the location and size of your malignant peripheral nerve sheath tumor, surgery can cause nerve damage and disability. In the case of tumors that occur in the arms and legs, limb amputation may be necessary.
In some cases your doctor may recommend radiation before surgery to shrink a tumor. That may make it more likely that the tumor can be removed completely.
- Radiation therapy. Radiation therapy uses powerful beams of energy, such as X-rays and protons, to kill cancer cells. Radiation may be used before surgery to shrink a tumor and make successful surgery more likely. After surgery, radiation therapy may be used to kill any cancer cells that might remain.
- Chemotherapy. Chemotherapy is a drug treatment that uses chemicals to kill cancer cells. If your malignant peripheral nerve sheath tumor has spread to other parts of your body, your doctor may recommend chemotherapy to control your symptoms and slow the growth of the cancer.
- Rehabilitation. After surgery, physical therapists and occupational therapists can help you recover function and mobility lost due to nerve damage or limb amputation.
Preparing for an appointment
If you have any signs or symptoms that worry you, make an appointment with your doctor.
If you're diagnosed with a malignant peripheral nerve sheath tumor, you'll likely be referred to a doctor who specializes in:
- Conditions that affect the nervous system (neurologist)
- Treating cancer (oncologist)
- Surgery involving bones (orthopedist)
- Surgery involving nerves (neurosurgeon)
Because appointments can be brief and because there's often a lot of ground to cover, it's a good idea to be well-prepared. Here's some information to help you get ready and know what to expect from your doctor.
What you can do
- Note symptoms you're experiencing. If you have had signs and symptoms of illness or are just not feeling well, write down those details before your appointment. Your doctor will also want to know when you first noticed these symptoms and whether they've changed over time.
- Make a list of your medications. Include any prescription or over-the-counter medications you're taking, as well as all vitamins, supplements and herbal remedies.
- Take a family member or friend along. Sometimes it can be difficult to remember all the information provided during an appointment. Someone who accompanies you may remember something that you missed or forgot.
- Write down questions to ask your doctor.
Questions to ask your doctor at your initial appointment include:
- What may be causing my symptoms or condition?
- Are there any other possible causes?
- What kinds of tests do I need?
- What do you recommend for next steps in determining my diagnosis and treatment?
- Are there any restrictions that I need to follow in the meantime?
Questions to consider if your doctor refers you to a specialist include:
- Do I have a malignant peripheral nerve sheath tumor?
- What are the goals of treatment in my case?
- What treatment do you recommend?
- Is it necessary to begin treatment right away?
- I have these other health problems. How can I best treat them together?
- What are the possible side effects of treatment?
- If the first treatment isn't successful, what will we try next?
- What is the outlook for my condition?
In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment at any time that you don't understand something.
What to expect from your doctor
Your doctor is likely to ask you a number of questions. Thinking about your answers ahead of time can help you make the most of your appointment. Your doctor may ask:
- What are your symptoms, if any?
- When did you first begin experiencing symptoms?
- How have your symptoms changed over time?
- Have you been diagnosed with or treated for any other medical conditions?
- What medications are you taking?