Schwannoma, also called neurilemoma, is a benign tumor that can arise from any nerve in the body, although it tends to favor certain nerves located in the head and neck along with nerves that are involved with flexing in the upper and lower extremities. The tumor is made up of Schwann cells, that grow abnormally. Normally Schwann cells coat the axon of neurons (nerve cells)
These tumors are non-aggressive and easily treated. Originating in the nerve sheath, the membrane that covers the nerve, they are usually easily separated from the nerve in surgery without any disturbance to the nerve's function. They can occur in children but more commonly affect young adults.