Schwannoma is a rare tumor of the sheath or lining around the peripheral nerves. It starts in the Schwann cells, which is how it gets its name. Schwann cells help form the cover around the nerves called the myelin sheath. Sometimes it’s called neurosarcoma or neurogenic sarcoma.
It is benign, usually slow growing, and painless. It stays on the outside of the nerve. Benign means it isn’t cancer. It won’t spread to other areas, and isn’t likely to cause death. But if it grows large enough to put pressure on the nerve, then pain, numbness, and even paralysis can occur.