What Are Plexiform Neurofibromas?

• Most plexiform neurofibromas are symptoms of a rare genetic disorder called neurofibromatosis. Neurofibromatosis is caused by genetic mutations of certain genes believed to function as tumor suppressors. 
• Some people inherit the mutated gene from a parent, and in other people, the mutation occurs for unknown reasons (spontaneous mutation).

Patients who have neurofibromatosis are routinely screened for the development of tumors such as plexiform neurofibromas. They can often be diagnosed with a physical examination. 

Magnetic resonance imaging (MRI) scans can allow for complete imaging of the growths.

• Surgery is often the primary treatment option for plexiform neurofibromas, but these tumors can be difficult to remove surgically because they are intertwined with normal tissue. 
• When it is not possible to remove all of a plexiform neurofibroma, a debulking procedure that removes a portion of the tumor may be performed. However, plexiform neurofibromas can grow back after surgery.
• Newer medications are being developed to treat plexiform neurofibromas, called MEK inhibitors, that can reduce the size of plexiform neurofibromas in many people with NF1. The MEK inhibitor selumetinib (Koselugo) was approved by the Food and Drug Administration (FDA) to treat symptomatic plexiform neurofibromas in children with NF1 and may be an option for some individuals who cannot have surgery. 

Plexiform neurofibromas may not cause any symptoms in themselves, but because they may be located on or near major organs, they can cause complications. 

Complications of plexiform neurofibromas may include: 

• Mast cells within plexiform neurofibromas can cause itching
• Depending on their size and location, some plexiform neurofibromas cause disfigurement which may change a person’s appearance
• They can press on important organs 
  • If they press on the airways or gastrointestinal tract, they can cause dysfunction
  • If they involve the peripheral nerves or spinal cord, they can cause pain, weakness, numbness, tingling, or bowel/bladder problems
• Plexiform neurofibromas may be slightly painful when bumped or pushed, though they usually do not cause severe pain
  • Seek medical care right away if you have been diagnosed with a plexiform neurofibroma and you experience severe pain
• Although plexiform neurofibromas are not cancerous (benign), they are at increased risk of becoming cancerous (malignant)
  • Cancerous plexiform neurofibromas are called malignant peripheral nerve sheath tumors (MPNSTs)
  • Treatment for MPNSTs may include one or more of the following: surgery, radiation, chemotherapy