Malignant Peripheral Nerve Sheath Tumor: Causes, Symptoms, and Treatment

Medically reviewed by Achuta Uppu, MD, Internal Medicine. Last reviewed: October 23, 2026.

What kind of doctor treats Malignant Peripheral Nerve Sheath Tumor?

A cancer doctor, called an oncologist, usually leads care for a malignant peripheral nerve sheath tumor. A surgeon who treats sarcomas, which are cancers of soft tissue, often removes the tumor. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.

What is malignant peripheral nerve sheath tumor?

A malignant peripheral nerve sheath tumor, or MPNST, is a cancer of the cells that form the sheath, the covering that protects the nerves outside the brain and spinal cord. It is a type of sarcoma, a cancer that grows in soft tissue such as muscle, fat, and nerves. MPNST grows quickly and can spread to other parts of the body. It is rare and is most common in young adults and middle-aged adults. It has other names, including neurofibrosarcoma and malignant schwannoma.

Symptoms

Some people with MPNST do not have symptoms at first. Later, when the tumor gets larger, symptoms can include:

  • Pain.
  • Weakness.
  • A growing lump under the skin.

Causes and who gets it

MPNST forms when the sheath cells that cover nerves grow and divide more than normal. It is more common in people with a genetic condition called neurofibromatosis type 1, or NF1. Most tumors that grow on nerves in people with NF1 are not cancer. Still, some people with NF1 develop MPNST. About 25% to 50% of people with MPNST have NF1. In rare cases, more than one member of a family has MPNST.

How doctors diagnose it

Doctors use scans such as MRI, CT, and PET to see where the tumor is and how big it is. They also check for signs that the tumor has spread to other parts of the body. A biopsy confirms the diagnosis, and it takes a small sample from the tumor with a needle. A pathologist, a doctor who studies tissue, looks at the cells under a microscope.

Treatment

Once MPNST is diagnosed, you may have surgery to remove the tumor and some of the tissue around it. Sometimes surgery is not an option, and then your doctor will talk with you about other choices. Radiation therapy, which uses high-energy rays to kill cancer cells, can be used before and after surgery. If the tumor cannot be safely removed, chemotherapy, which is cancer-fighting medicine, can shrink it and make it easier to remove. Chemotherapy can also be used when MPNST has spread to other parts of the body. It is important to talk with a team of specialists to decide the right treatment for you.

When to see a doctor

See a doctor right away if you notice a growing lump under the skin, pain, or weakness. MPNST grows quickly and can spread, so early detection and treatment are important. If you have NF1, ask about yearly exams with a doctor experienced in NF1.

How a direct primary care or concierge doctor fits in

A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. It can look into a new lump or pain, order first tests, and refer you to a cancer team. It can also help keep follow-up visits organized for people who have NF1.

Common questions

Is a malignant peripheral nerve sheath tumor cancer?

Yes, it is a cancer. It is a type of sarcoma that grows in soft tissue.

Yes, it is more common in people with NF1. Most nerve tumors in NF1 are not cancer, but some people with NF1 develop MPNST.

Can a malignant peripheral nerve sheath tumor spread?

Yes, it grows quickly and can spread to other parts of the body. Doctors use scans to check for signs of spread.

What affects the outlook for a malignant peripheral nerve sheath tumor?

It depends on several things, including where the tumor is and whether the cancer has spread. How much of the tumor was taken out during surgery also matters. Working with a team of experts soon after diagnosis can improve your chances.

Sources

  1. National Cancer Institute - Malignant Peripheral Nerve Sheath Tumor
  2. American Cancer Society - Neurofibromatosis Type 1 (NF1)
  3. National Organization for Rare Disorders - Malignant peripheral nerve sheath tumor

Medical Disclaimer

This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.