Plexiform neurofibromas are benign tumors that grow on nerves. These tumors usually affect people -- most often children -- with the genetic condition neurofibromatosis type 1 (NF1).

Plexiform neurofibromas can form just about anywhere on the body -- on the face, arms, legs, back, stomach, and belly. When they grow big enough, they can cause pain and other problems and change your appearance.

If you or your child has plexiform neurofibromas, let your doctor know if the tumors grow and cause problems. Surgery is often the only option that can remove these tumors and relieve the pain and other symptoms that come with them. Newer therapies can help shrink these tumors.

What Are the Possible Health Effects of Plexiform Neurofibromas?

Sometimes they don't cause any symptoms at first. You may not know that they’re there until they start to grow.

When these tumors do get larger, they can press on organs and tissue inside the body. When they get big enough, they can affect many different parts of the body.

Some of the problems they may cause include:

Pain. When the tumors grow into other organs and tissues, the pressure can be painful. The pain may get worse if you hit or bump the growths.

Vision loss. Tumors that form behind the eye can affect vision and make it hard to move the eyes. Rarely, tumors in the back of the eye can lead to loss of eyesight. An eye doctor can check your or your child’s vision during routine visits.

Trouble breathing or swallowing. Tumors can press on airways and make it hard to breathe. A tumor in the neck can make it difficult to swallow food, too.

Weakness. Growths can press on the spinal cord and nerves and cause weakness and make it hard to walk or move.

Curved spine. The tumors can create a curve in the spine called scoliosis. A doctor can monitor the curve with X-rays. A mild curve may not need treatment. A more severe one can cause pain and might require surgery to straighten out.

Problems with speech and learning. Some children with plexiform neurofibromas have more trouble learning than other children their age. NF1 doesn't affect intelligence, but it can make it harder for kids to pay attention or follow instructions in school. Some children have trouble speaking clearly and may need speech therapy.

Trouble going to the bathroom. Plexiform neurofibromas in the pelvis can press on the bladder or other related body parts and make it hard to pee.

Do plexiform neurofibromas turn into cancer?

These tumors don't often turn into cancer, but it can happen when other genes are affected. About 10% of them change into a type of cancer called a malignant peripheral nerve sheath tumor (MPNST).

MPNST is a very aggressive type of cancer. It can spread to other parts of the body, like the lungs and bones. Quick treatment is important.

Because doctors don't have tests for MPNST, it's important to watch for signs. Let your doctor know if:

  • The tumor is painful on its own, without being bumped or injured
  • The tumor grows quickly
  • It changes shape or color, or it feels hard
  • You or your child has any new weakness or numbness

How can they change your appearance?

Tumors that are small and deep inside the body may be hard to see. But if they're right under the skin, these bumps can become noticeable as they grow, especially when you have a lot of them.

These tumors can change the shape of a person’s bones in a way that affects their appearance. These changes can make both kids and adults feel self-conscious about the way they look.

Procedures and medications to make these growths smaller can help you or your child feel more comfortable with these tumors. Ask your doctor for advice on treatments. If the condition makes you or your child feel anxious or depressed, a therapist or other mental health professional could help.

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SOURCES:

Adolescent Health, Medicine & Therapeutics: "Natural History and Disease Burden of Neurofibromatosis Type 1 With Plexiform Neurofibromas: A Systematic Literature Review."

Children's National: "Pediatric Plexiform Neurofibromas."

Medicine: "Plexiform Neurofibroma."

National Institute of Neurological Disorders and Stroke: "Neurofibromatosis Fact Sheet."

Nerve Tumours UK: "The Child with Neurofibromatosis Type 1 (NF1): A Guide for Parents."

The University of Alabama at Birmingham: "Complications of Neurofibromatosis Type 1 (NF1)."

Washington University in St. Louis: "Living with Neurofibromatosis Type 1: A Guide for Adults."

Washington University Physicians: "Nerve Tumors."