When you or your child has a plexiform neurofibroma, a doctor will want to check it out and monitor it closely to be sure it’s not causing problems. These tumors usually grow slowly, but they can get very large. They start inside branches of nerves, but may spread to nearby tissue.

They may press on important organs and cause serious side effects, including significant pain, numbness, trouble breathing or moving, or bowel and bladder problems. Depending on where the tumors are, they may also alter the way you look or the way you think and learn. But only a small number of people have symptoms like these and need treatment.

The doctor will want to monitor these tumors to see where they are in the body and how fast they’re growing. They may need to use an MRI for a better picture of what’s going on.

Until recently, removing the tumor with surgery was the only option to treat plexiform neurofibromas. Now doctors also use medications to help slow down tumor growth or shrink tumors that can’t be surgically removed.


Surgery to remove the entire tumor is a cure for about 75% of people who try it. For some people, the tumor grows back after surgery.

Surgery may leave some nerve damage afterward. This can cause complications such as numbness or trouble moving some parts of the body. Some people need physical or occupational therapy after surgery to help keep their muscles and joints active, get feeling and use back, and prevent stiffness.

An operation to remove the whole tumor is not a safe option for everyone. If the tumor has spread into normal tissue, a doctor may not be able to remove it without causing damage to nearby organs. Often doctors will instead take out only a part of a tumor to make it smaller and limit the harm or discomfort it could cause. This is called a debulking procedure.

Nonsurgical Treatments

A twice-daily pill. The FDA recently approved a drug called selumetinib (Koselugo) to help treat plexiform neurofibromas that are causing symptoms but that doctors can’t remove with surgery. They may also use it to help put off surgery or avoid it altogether.

Selumetinib works by blocking signals from the abnormal protein that causes the tumors to grow. This slows down tumor growth.

It comes as a capsule that you take by mouth twice a day on an empty stomach. It’s not for children under 2 years old.

This medicine may cause some GI symptoms when you take it, such as:

  • Vomiting
  • Constipation
  • Stomach pain
  • Nausea

It may also lead to:

  • Dry skin
  • Headache
  • Mouth ulcers
  • Itching
  • Redness around the fingernails
  • Nose bleeds
  • Fatigue
  • Loss of appetite
  • Hair loss or hair color changes

Medication applied to the skin. Researchers are testing a treatment called sirolimus. So far, there have been promising results showing that it can help ease pain and make plexiform neurofibromas smaller. In clinical trials, using sirolimus slowed down the progression of tumors by about 4 months. Experts think it could be a good option for certain people who have severe pain, fast growth, or tumors that are hard to remove with surgery.

If the Tumor Becomes Cancerous

Rarely, plexiform neurofibromas can become cancerous tumors called malignant peripheral nerve sheath tumors (MPNST). But the odds of this are pretty low. The lifetime risk of developing MPNST is 8% to 12%.

New symptoms or changes in the tumor can be a sign that it is becoming cancerous. Tell your doctor if the tumor is:

  • Growing quickly
  • Very painful
  • Getting harder

If the tumor has become cancerous, you or your child may need different treatment, including:

  • Radiation
  • Chemotherapy
  • Surgery
  • A combination of all three

© 2022 WebMD, LLC. All rights reserved.

Show Sources

Photo Credit: Wavebreakmedia


Children’s Tumor Foundation: “Plexiform Neurofibromas In Neurofibromatosis Type 1.”

NHS: “Neurofibromatosis type 1: Treatment.”

Children’s National: “Pediatric Plexiform Neurofibromas.”

American Academy of Pediatrics: “Health Supervision for Children With Neurofibromatosis.”

Mayo Clinic: “Peripheral nerve tumors.”

Medline: “Selumetinib.”

Neuro-Oncology: “Sirolimus for progressive neurofibromatosis type 1–associated plexiformneurofibromas: a Neurofibromatosis Clinical Trials Consortiumphase II study.”