A neurofibroma is a growth, or tumor, that forms on or around a nerve. Neurofibromas are a feature of neurofibromatosis, or NF — a progressive disease that causes tumors to grow in various parts of the body. However, it’s possible to have a single neurofibroma without having NF, and some people with NF don’t get any tumors.
NF comes in two forms. About 90 percent of NF cases are NF1 — a leading genetic disorder in the United States, affecting about 100,000 Americans according to the March of Dimes. The disease usually appears by the time a child reaches puberty. In most cases, NF symptoms are mild, and sometimes not even noticeable. However, in a small but significant percentage of cases, NF1 causes severe and debilitating symptoms.
The nature of the symptoms and how they affect the patient varies with the location of the neurofibromas and how much pressure they put on the nerves and surrounding tissue. Some people develop visible lumps or numerous brown patches on the skin, called “café au lait” marks. Sometimes bone deformities occur and other times patients develop scoliosis, an abnormal curvature of the spine. The tumors may grow on the optic nerve, occasionally leading to blindness. Children with NF1 may have learning disabilities.
Much more rare than NF1, NF2 is caused by a defect in a different gene. It tends to be a much more serious disease, possibly causing tumors in the brain, spinal cord and the nerves of the ear, leading to hearing and balance problems. It may also cause cataracts and other symptoms. The skin tumors and café au lait spots are less common in NF2, and symptoms usually don’t begin until after puberty.
There isn’t a cure for neurofibromatosis. However, treatment, which is aimed at easing the various symptoms and complications, is often successful. In some cases, it’s necessary to surgically remove all or part of the tumors or to shrink them with radiation.
The gene defects that cause neurofibromatosis may be inherited or they may arise spontaneously as a result of genetic mutation. Once the mutation occurs, however, that individual can pass the disease to his or her children. Genetic testing and counseling may be helpful to people with NF who are considering having children.