Neurofibromatosis

Neurofibromatosis
Back of an elderly woman with neurofibromatosis type 1
Specialty	Neurosurgery, neurology, Neuro-oncology
Symptoms	Small lumps within the skin, scoliosis, hearing loss, vision loss[1]
Usual onset	Birth to early adulthood[1]
Duration	Life long[1]
Types	Neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2), schwannomatosis[1]
Causes	Genetic[1]
Diagnostic method	Symptoms, genetic testing[2]
Treatment	Surgery, radiation therapy[2]
Prognosis	NF1: variable, but most of the time normal life expectancy[1] NF2: shortened life expectancy[1]
Frequency	1 in 3,000 people (United States)[1]

Neurofibromatosis (NF) refers to a group of three distinct genetic conditions in which tumors grow in the nervous system.^[1] The tumors are non-cancerous (benign) and often involve the skin or surrounding bone.^[1] Although symptoms are often mild, each condition presents differently. Neurofibromatosis type I (NF1) is typically characterized by café au lait spots (light-brown flat patches of skin), neurofibromas (small bumps in or under the skin), scoliosis (side-way curvature of the back), and headaches.^[2] Neurofibromatosis type II (NF2), on the other hand, may present with early-onset hearing loss, cataracts, tinnitus, difficulty walking or maintain balance, and muscle atrophy.^[2] The third type is called schwannomatosis and often presents in early adulthood with widespread pain, numbness, or tingling due to nerve compression.^[3]

The cause is a genetic mutation in certain oncogenes.^[1] These can be inherited, or in about half of cases spontaneously occur during early development.^[1] Different mutations result in the three types of NF.^[4] Neurofibromatosis arise from the supporting cells of the nervous system rather than the neurons themselves.^[1] In NF1, the tumors are neurofibromas (tumors of the peripheral nerves), while in NF2 and schwannomatosis tumors of Schwann cells are more common.^[1] Diagnosis is typically based on symptoms, examination, medical imaging, and biopsy.^[5][3] Genetic testing may rarely be done to support the diagnosis.^[2]

There is no known prevention or cure.^[1][2] Surgery may be done to remove tumors that are causing problems or have become cancerous.^[1] Radiation and chemotherapy may also be used if cancer occurs.^[1] A cochlear implant or auditory brainstem implant may help some who have hearing loss due to the condition.^[1]

In the United States, about 1 in 3,500 people have NF1 and 1 in 25,000 have NF2.^[1] Males and females are affected equally often.^[2] In NF1, symptoms are often present at birth or develop before 10 years of age.^[1] While the condition typically worsens with time, most people with NF1 have a normal life expectancy.^[1] In NF2, symptoms may not become apparent until early adulthood.^[1] NF2 increases the risk of early death.^[1] Descriptions of the condition occur as far back as the 1st century.^[6] It was formally described by Friedrich Daniel von Recklinghausen in 1882, after whom it was previously named.^[4]