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Most peripheral nerve tumors are benign (not malignant). They affect nerves either directly, by growing within them, or indirectly by pressing against them.
This is the most common type of peripheral nerve tumor in adults. Schwannomas are nonmalignant and usually isolated lesions, except when they are associated with neurofibromatosis type 2 (NF2). They typically arise from a single fascicle (a bundle within the main nerve) and displace rather than invade the rest of the nerve. They may occur anywhere. Most patients with schwannomas in the limbs may notice a new mass and may experience some symptoms, especially if it is bumped. Vestibular schwannoma is one type which occurs near the brainstem and cerebellum on a nerves that control balance. (See more details under acoustic neuroma.) These patients may present with balance difficulties or hearing problems. In general, these tumors grow slowly.
Neurofibromatosis Type 2. Patients with this condition may develop tumors on both sides of the brain. Symptoms include progressive hearing loss, poor balance, headaches, facial pain or numbness. If the tumors are not treated and continue to grow, NF2 can affect nearby nerves, including the brain stem, and cause death.
This type of peripheral nerve tumor most commonly develops in individuals who have neurofibromatosis. Neurofibromatosis type 1 occurs in about 1 in 4,000 people in the United States. The vast majority of patients with NF1 have mild symptoms from neurofibromas. These patients however can develop other conditions and symptoms related to them, such as severe scoliosis (curvature of the spine), enlargement or deformity of bones other than the spine and a tumor on the eye nerve (optic glioma).
Dumbell tumor
These rare schwannomas or neurofibromas often grow to resemble a large dumbbell based on the bony confines which shape their growth and extension. They may occur in the spine (and extend out the natural openings in the spinal cord) or in the lower abdomen near the hip (the sciatic notch), and extend from the pelvis to the abdomen. They are often considered inoperable because they are so intertwined with important nerves. Mayo surgeons have a large experience in successfully removing these challenging tumors.
In a recent report in the Journal of Neurosurgery, Mayo surgeons describe how high-resolution MR imaging is helping them identify cases where the sciatic notch tumors displace rather than directly involve the sciatic nerve. These tumors can be safely removed using a team approach with colon and rectal surgeons, urologists and neurosurgeons.
These are benign, soft lumps under the skin caused by slow-growing fat cells. They usually appear on the neck, shoulders, back or arms, most often between ages 40 to 60. In most cases, they do not cause pain or other problems, but they should be examined and monitored through regular check-ups. When they occur near nerves, they may compress them.
Ganglion cysts most commonly form from joints. They often occur at the wrist or at the base of a finger, but they can occur elsewhere and compress neighboring nerves. While some cysts form as a result of an injury, most cysts have no known cause. The cysts can increase or decrease in size. Some ganglion cysts go away without medical treatment. The lump can cause pain and interfere with use of a limb. In those cases, the lump should be surgically removed. Read more about treatment of ganglion cysts.
A benign tumor made up primarily of fibrous tissue.
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