Malignant Peripheral Nerve Sheath Tumors

Rare cancers called malignant peripheral nerve sheath tumors (MPNSTs) develop in the protective covering of nerves. These nerves, called peripheral nerves, extend from the spinal cord throughout the body. Previously, these tumors were known as neurofibrosarcomas.

MPNSTs can form anywhere in the body, but they frequently appear in the muscles and tissues of the arms, legs, and torso. A common symptom is pain and weakness in the affected area. Often, a noticeable lump or swelling also develops.

The primary treatment for MPNSTs is surgery to remove the tumor. Depending on the situation, radiation therapy and/or chemotherapy might also be used. This combination of treatments helps to target the cancer cells and reduce the risk of recurrence.

Sometimes, tumors grow around nerves outside the brain and spinal cord. These are called malignant peripheral nerve sheath tumors. They can cause problems that quickly get worse.

One common sign is pain in the area where the tumor is developing. This pain can be pretty intense. Another symptom is weakness or trouble moving the part of the body where the tumor is located. You might notice a noticeable lump under your skin, which also could be a sign of this type of tumor.

If you're experiencing any of these symptoms, or any other unusual symptoms that worry you, it's important to see a doctor. These tumors are uncommon, so your doctor may first try to rule out other, more frequent causes for your symptoms. It's always best to get checked out if you have concerns.

If you're experiencing persistent symptoms that concern you, schedule a visit with your doctor. Rare tumors called malignant peripheral nerve sheath tumors are a possibility, but your doctor will likely first investigate more common explanations for your symptoms.

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Many malignant peripheral nerve sheath tumors (MPNSTs) don't have a clear cause. Doctors know these cancers start when cells in the protective covering around nerves have changes in their DNA. Think of DNA as a cell's instruction manual. These changes tell the cells to grow and multiply much faster than normal. Normally, cells have a natural life cycle, and some cells die off as part of this process. But the abnormal cells in MPNSTs keep living, even when healthy cells would normally die.

This uncontrolled growth of cells forms a mass called a tumor. This tumor can invade and damage nearby healthy tissue. Eventually, these abnormal cells can travel to other parts of the body, causing problems there as well.

Some things can raise your chances of getting a type of cancer called a malignant peripheral nerve sheath tumor (MPNST). These include:

• Past radiation treatment: If you've had radiation therapy for cancer, there's a chance an MPNST could develop in the area that was treated, possibly 10 to 20 years later. This is why it's important to follow up with your doctor after radiation treatment, and to report any new symptoms in the affected area.

• Previous non-cancerous nerve tumors: Sometimes, an MPNST can start from a non-cancerous nerve tumor. One example is a neurofibroma. If you have a history of these types of tumors, you might have a higher risk of developing an MPNST.

• Inherited risk: Some people inherit a genetic condition called neurofibromatosis type 1 (NF1). This condition makes them more prone to developing tumors, including MPNSTs, in their nerves. Having NF1 significantly increases your risk of these tumors. It's essential to be aware of this potential risk if you have a family history of NF1.

Diagnosing malignant peripheral nerve sheath tumors involves several steps to find out what's going on and what the best treatment might be.

Checking the nervous system (neurological exam): A doctor will carefully examine your nervous system to look for signs that might point to a tumor. This helps them narrow down the possibilities.

Taking pictures of the body (imaging tests): Different imaging tests create pictures of the inside of your body. These pictures can show the size of the tumor and whether it has spread. Some common imaging tests include:

• MRI (magnetic resonance imaging): This creates detailed images of soft tissues in the body, including nerves.
• MRI neurography: This type of MRI is specifically used to get detailed images of the nerves.
• CT scan (computed tomography): This test uses X-rays to create cross-sectional images of the body, which can help show the tumor's location and extent.
• PET scan (positron emission tomography): This test uses radioactive material to create images of areas of high metabolic activity in the body. Sometimes this can help show if the tumor is active or growing.

Taking a tissue sample (biopsy): To confirm a diagnosis and learn more about the tumor, a small piece of tissue (a biopsy) needs to be taken from the tumor. This is done in several ways:

• Needle biopsy: A thin needle is used to take a small sample of tissue directly from the tumor.
• Surgical biopsy: In some cases, a small surgery is needed to safely remove a sample of the tumor for testing.

Lab tests on the tissue sample: The lab will examine the tissue sample under a microscope. This lets the doctors know if the cells are cancerous and what type of cancer it is. Additional tests on the sample can provide even more information about the specific characteristics of the cancer cells. This detailed information is crucial for creating a personalized treatment plan.