Schwannoma is a slow-growing benign tumor of the nerve sheath (lining of the nerve). Another term to describe this tumor is neurilemmona. These tumors affect the peripheral nerves. Peripheral nerves are the nerve roots as they leave the spinal cord. Schwannomas/neurilemmonas only affect sensory nerve roots. They usually occur in the head, upper trunk, and extremities (arms and legs).
Benign means the tumor doesn’t spread to other areas of the body. Even though it isn’t considered mlignnant, a benign tumor can cause pain, swelling, loss of motion, weakness, and deceased function of the affected part.
At first, the schwannoma/neruilemmoma grows so slowly there are no symptoms. A painful lump in the arms or upper body may be the first sign. Sometimes there is a mild loss of sensation. Tapping (or bumping) the affected nerve can cause numbness, tingling, or even a shock sensation down the nerve pathway.
Since only sensory nerves and not motor nerves are affected, there usually isn’t a loss of strength or the development of muscle atrophy (wasting). The diagnosis can be delayed by months to years. Many of the tumors are found when X-rays are taken for something else. If they aren’t causing any problems, no treatment is necessary. Surgery may be needed to remove the tumor and reduce symptoms from pressure on the nerve.