By Neurosurgery Singapore
What is Neurofibromatosis?
Neurofibromatosis refers to three different conditions involving the development of tumors that may affect the brain, spinal cord, and the nerves that send signals between the brain and spinal cord and all other parts of the body. Most tumors are non-cancerous (benign), although some may become cancerous (malignant).
The conditions are:
- Neurofibromatosis type 1 (NF1), also known as von Recklinghausen disease
- Neurofibromatosis type 2 (NF2)
- Schwannomatosis (SWN)
What are some symptoms of Neurofibromatosis?
There are three types of neurofibromatosis, each with different signs and symptoms.
Neurofibromatosis 1 (NF1) is usually diagnosed during childhood. Signs are often noticeable at birth or shortly afterward and almost always by age 10. Signs and symptoms are often mild to moderate, but can vary in severity.
Signs and symptoms include:
- Multiple freckles in the armpit or groin area
- Tiny growths in the iris (colored area) of the eye; these are called Lisch nodules and usually do not affect eyesight.
- Bone deformities, including a twisted spine (scoliosis) or bowed legs
- Tumors along the optic nerve, which may cause eyesight problems
- Nerve-related pain
- High blood pressure
- Learning disabilities
- Large head size
- Short stature
Neurofibromatosis 2 (NF2) is much less common than NF1. Signs and symptoms of NF2 usually result from the development of benign, slow-growing tumors in both ears (acoustic neuromas), which can cause hearing loss. Also known as vestibular schwannomas, these tumors grow on the nerve that carries sound and balance information from the inner ear to the brain.
Signs and symptoms generally appear during the late teen and early adult years, and can vary in severity. Signs and symptoms can include:
- Loss of hearing
- Weakness of the muscles of the face
- Poor balance
- Uncoordinated walking
- Cataracts (cloudy areas on the lens of the eye) that develop at an unusually early age
This rare type of neurofibromatosis usually affects people after age 20. Symptoms usually appear between ages 25 and 30. Schwannomatosis causes tumors to develop on the cranial, spinal and peripheral nerves — but rarely on the nerve that carries sound and balance information from the inner ear to the brain. Tumors don’t usually grow on both hearing nerves, so people who have schwannomatosis don’t experience the same hearing loss as people who have NF2.
Symptoms of schwannomatosis include:
- Pain from the enlarging tumors
- Numbness and tingling of the fingers or toes
- Weakness in the fingers and toes
- Chronic pain
- Loss of muscle
What are possible causes of Neurofibromatosis?
NF1 is caused by mutations in the gene that controls production of a protein called neurofibromin (neurofibromin 1). This gene is believed to function as a tumor suppressor. In about 50% of people with NF1, the disorder results from gene mutations that occur for unknown reasons (spontaneous mutation). In others with the disorder, NF1 is inherited.
NF2 results from mutations in a different tumor-suppressing gene. Some people with NF2 experience a gene mutation that occurs for unknown reasons, while others inherit it from their parent(s).
While schwannomatosis is not well understood, it is estimated that 85% of cases have no known cause and 15% are inherited.
“There is a 50-percent chance that each child of a parent with NF1 or NF2 will inherit the gene and develop NF1 or NF2 (respectively) — this is known as autosomal dominant inheritance pattern”
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What types of diagnosis?
Our Neurosurgeon will talk with you about your general health and medical history, and ask questions about the location, nature, severity, and duration of your symptoms.
After a careful history and examination, our doctor may order several tests including the following.
- Electromyography (EMG)/nerve conduction study (NCS), to measure electrical pathways in the nerves.
- A biopsy, so that a pathologist can diagnose a neurofibroma or schwannoma by looking at a piece of the tumor under a microscope
Possible treatment methods?
Mild cases of NF1, NF2 and schwannomatosis do not cause severe problems, and affected people may require no treatment beyond observation and regular checkups and symptom management. Children born with neurofibromatosis should be monitored by our doctor, who can help detect complications such as hearing problems, bone deformities and changes to skin lesions.
Tumors and bone changes caused by neurofibromatosis can be treated with surgical and nonsurgical methods. Care should be coordinated by a genetics expert, and may involve neurologists, orthopaedic surgeons and other specialists.
If a schwannoma or neurofibroma causes significant pain or loss of neurological function, compresses a nearby structure or shows rapid growth on imaging, our doctor may recommend removing it surgically and/or by using radiation.