plexiform neurofibroma
(PLEK-sih-form NOOR-oh-fy-BROH-muh)
A tumor that forms in the tissue that covers and protects the nerves. Plexiform neurofibromas can occur anywhere in the body outside of the brain and spinal cord. They can occur on the face (including around the eye), neck, arms, legs, back, chest, abdomen, and internal organs. Large tumors can cause a nerve to become thick and misshapen, which can affect the structure of nearby bone, skin, and muscle. Plexiform neurofibromas can cause severe pain, mobility problems, vision and hearing loss, high blood pressure, and other medical problems. Most plexiform neurofibromas are not cancer, but some may become cancer. They most commonly occur in children who have a rare genetic condition called neurofibromatosis type 1.