This type of neurofibromatosis is also known as von Recklinghausen’s disease, or peripheral neurofibromatosis. Neurofibromatosis type 1 (NF1) is the most common of the three types of this disease.
One of the most characteristic symptoms is the presence of coffee-coloured patches (cafe-au-lait spots) on the skin, which appear during childhood. In many affected individuals, this may be the only symptom present. These spots usually increase in number and size with age. Freckles can sometimes be observed in the groin and armpit areas as well.
Most adults usually develop benign tumors on or immediately under the skin, which are usually located in nerves close to the spine or in other areas of the body. A symptom that often develops during childhood is the presence of benign growths in the iris, known as Lisch nodules, which do not affect vision. Some individuals may develop tumors in the optic nerve (optic nerve gliomas), which can lead to total or partial loss of vision, although they sometimes do not affect vision at all. Other symptoms of this disorder are hypertension, short stature, head larger than normal (macrocephaly), skeletal abnormalities such as abnormally curved legs or abnormally curved spine (scoliosis). Children with this disorder often present with learning difficulties, such as attention deficit and hyperactivity (ADHD).
NF1 is a progressive disorder whose symptoms usually worsen with time, reaching moderate to severe degree, although a small number of patients may present with symptoms that remain unaltered. When complications derived from the disease arise, they usually do not threaten the patient’s life; in fact, individuals with this disorder have a normal life expectancy.
Although no cure for neurofibromatosis type 1 exists, some of its symptoms can be treated. Tumors can be surgically removed, although they often reappear; likewise, optic nerve gliomas can be treated with surgery and/or chemotherapy. Scoliosis and abnormally curved legs can also be treated with surgery or orthopedics.
This type is much more uncommon than NF1. One of the main symptoms are vestibular schwannomas, which are benign tumors located in the nerve that connects the brain and the ear (the eighth cranial nerve) and which usually occur around age 30. Their name is due to the fact that they are originated from Schwann cells, whose function is to protect nerve cells. These tumors sometimes press and damage the nerves around them and, depending on their location, can be highly dangerous.
Individuals with neurofibromatosis type 2 (NF2) are at a higher risk of suffering from other benign tumors in the nervous system, such as brain or spinal tumors. Patients can also suffer from tumors (schwannomas) in the skin, as well as eye disorders such as cataracts, but the presence of cafe-au-lait spots or neurofibromas is not as common. Symtpoms usually start presenting between ages 18 and 22, and the most common first symptom is often hearing loss or ear buzzing.
As in the case of NF1, there is no cure for neurofibromatosis type 2, but surgery can help manage the resulting symptoms. Early surgery when vestibular schwannomas are still small is sometimes recommended in order to remove the whole tumor and preserve hearing and balance. Radiosurgery and chemotherapy treatments are being tested for this type of tumors, but the risks of these procedures in relation to their efficiency are yet to be assessed. Surgery can also be used to correct cataracts and potential retinal abnormalities, as well as for spinal tumors, although they often do not cause any symptoms.
It is a recently recognized type of neurofibromatosis that was formerly included within NF2. It is the least common form of the disease. The main feature is the development of schwannomas in different areas of the body, excluding the vestibular nerve. When schwannomas increase in size, they cause very severe pain, which is the main symptom of this disorder; the intensity of the pain varies among individuals. Other symptoms such as numbing, tingling, or weakness in fingers and toes are sometimes present. These patients never present with neurofibromas. Approximately one third of people affected by this disorder have tumors restricted to only one area of the body. The number of tumors varies among individuals.
Surgery is again the most effective treatment. Schwannomas are usually removed to mitigate pain, although they sometimes develop again. Treatment often includes painkillers to manage pain.