NF1 is characterized by prominent skin features (hyperpigmented macules, termed café-au-lait spots, and nerve tumors that may or may not be close to the skin), optical tumors and other central nervous system tumors, certain bony abnormalities, some learning deficits and increased risk of certain non-nervous system cancers. NF1 is usually noticed during childhood with the development of skin findings.
Because of the complexity of the disorder, patients with NF1 are often best served by being followed at a neurofibromatosis center with a multidisciplinary team including genetics, neurology, neurosurgery, ophthalmology, orthopedics, dermatology, plastic surgery, neuropsychology and oncology. Patients with NF1 should undergo physical examinations twice a year, at least until age five, and yearly thereafter. Because of certain risks associated with these patients, blood pressure should be checked at least twice yearly. Special attention should be paid to early detection of scoliosis, evidence of limb bowing or pseudarthrosis, presence of or change in the cutaneous manifestations, and signs of precocious or delayed puberty. Head circumference should be checked regularly for signs of rapid growth, particularly in the first three years of life. Behavior and development should be followed carefully for signs of learning disability and ADHD. Patients with NF1 should also undergo yearly neurologic and ophthalmologic evaluation.
The symptoms of NF1, also called von Recklinghausen disease, vary widely from person to person. Most people with NF1 will have some but not necessarily all of the following:
- Café-au-lait spots - flat, brown spots that usually appear during first year of life, but can be present at birth. They typically increase in number and size with age, but often fade later in life. About 25 percent of the normal population has one-to-three spots. More than 95 percent of patients with NF1 have them. Half of children with more than six spots and no other features of NF1 will later go on to meet criteria for the disease.
- Neurofibromas - benign tumors of the coverings of the nerves. There are three main types:
- Cutaneous neurofibromas are soft fleshy tumors arising from the peripheral nerve sheath, usually appearing in late childhood or young adulthood. They can become cosmetically significant and can cause itching or pain. They do not become malignant.
- Subcutaneous neurofibromas are firm, tender nodules along the course of peripheral nerves that usually appear during adolescence or young adulthood.
- Plexiform neurofibromas can involve long portions of one nerve or bundles of nerves. They can be deep inside the body and able to be seen only with scans, or they can be superficial and involve the sin, extremities, head or neck. They are usually not apparent in infancy though the skin overlying it may be darker and/or thickened. They tend to enlarge with age, and can become severely disfiguring.
- Freckling in the armpits and groin – usually not present at birth, but develops during childhood. It most commonly occurs in the armpit or upper thigh areas, but can occur in other areas, particularly in skin folds.
- Optic pathway gliomas (brain tumors)
- Lisch nodules - raised, usually pigmented, bumps on the iris of the eye. They rarely cause clinically significant symptoms and are benign.
- Bone abnormalities such as:
- Pseudarthrosis – also called false join. This occurs in up to five percent of NF1 patients. This abnormality results from thinning of the long bone cortex, followed by fracture and impaired healing. Half of cases occur before age two.
- Sphenoid dysplasia - malformation of the eye socket. This can be a disfiguring complication. It can occur with or without an associated plexiform neurofibroma.
- Vertebral dysplasias - abnormal shape of the bones of the spine
- Short stature and scoliosis - curvature of the spine. Scoliosis can occur in up to 25 percent of patients. This is most common in girls. Children with NF1 and scoliosis should be referred to an orthopedist with experience treating NF patients.
- Macrocephaly – large head size. This occurs in up to half of children with NF1. It is usually due to increased brain size, the cause of which is unclear.
- Learning problems and attention deficit disorder - fairly common but tend to be relatively mild.
To date, no effective medical treatment is available for prevention or reduction of neurofibromas. Timing and extent of surgical treatment remains variable and controversial.
For cutaneous and subcutaneous neurofibromas, surgery is usually reserved for patients with significant discomfort or with cosmetically significant lesions. Laser therapy can also be effective, particularly if a large number of neurofibromas are being treated at one time. It is typical that neurofibromas come back, even after treatment.
Plexiform neurofibromas are very challenging to treat. Because they are often large, irregular in shape, prone to bleeding and frequently involve numerous nerves, they are almost impossible to remove completely. Their unpredictable growth patterns also make appropriate treatment choices more difficult. Surgical therapy is generally reserved until the lesion is causing impairment of functioning or discomfort or is cosmetically significant. Spinal plexiform neurofibromas may also be surgically excised, but total removal is often not possible. Regrowth can occur. No medications for treatment of plexiform neurofibromas have been approved, but clinical trials for medical therapy are underway.