Neurofibromas are benign (noncancerous) tumors that grow on nerves in the body. Most neurofibromas occur in association with a genetic disorder. Solitary neurofibromas can also occur in otherwise healthy people; these are called sporadic neurofibromas.
Neurofibromatosis type 1, or NF1, is a genetic disorder characterized by multiple neurofibromas, along with other physical exam findings.
Neurofibromas: What You Need to Know
Neurofibromas can grow on nerves in the skin (cutaneous neurofibroma), under the skin (subcutaneous) or deeper in the body, including in the abdomen, chest and spine.
Neurofibromas can grow sporadically. Sporadic neurofibromas typically grow on the skin.
People with NF1 are predisposed to developing multiple neurofibromas. Most of these tumors do not hurt or cause problems, but some may itch or be painful.
Treatment consists of observation and, if necessary, surgical removal. Researchers are looking into various medicines to shrink neurofibromas in patients with NF1.
What causes neurofibromas?
A person can have a neurofibroma without having neurofibromatosis (NF). The cause of a sporadic neurofibroma is not known, although researchers are exploring the role of trauma. Neurofibromatosis is a genetic disease caused by a mutation in a gene responsible for a protein that regulates nerve tissue growth, and can be inherited.
Neurofibromas appear as one or more lumps on or under the skin. They may be painful or itch, but many do not cause any symptoms.
Neurofibromas growing deep in the body can cause pain, numbness, tingling or weakness if they press on nerves. This is more likely to be associated with NF1 than sporadic neurofibromas.
A severely painful neurofibroma should be looked at by a doctor who can make sure it has not become cancerous.
After a careful history and examination, the doctor may order several imaging studies including:
EMG/NCV: electromyography, a study that measures electrical pathways in the nerves
A pathologist can make a definitive diagnosis of a neurofibroma by looking at a piece of the tumor under a microscope.
Currently there is no medical treatment for neurofibromas, but NF1 researchers are exploring potential therapies, including drugs called MEK inhibitors, which block a particular protein associated with abnormal cell growth.
Most sporadic neurofibromas do not cause pain and can be managed without surgery. Sometimes after consulting with their doctor, people will choose to have sporadic neurofibromas surgically removed for cosmetic reasons or because the neurofibroma is growing in a location where it is bothersome.
If a tumor begins to cause significant pain, is associated with loss of neurological function, compresses a nearby structure or shows rapid growth on imaging, the doctor may recommend removing the neurofibroma surgically.
Depending on the location and size of the tumor and its involvement with the nerve, this surgery can be very challenging, requiring the skill of only the most experienced surgeons. A team approach is necessary, with neurosurgeons working together with plastic and reconstructive surgeons and other experts.