A schwannoma is a kind of tumor originating from the Schwann cells. The insulating myelin sheath which covers peripheral nerves is produced by the Schwann cells. Hence, one kind of tumor originating from the Schwann cells is called a schwannoma.

Schwannomas are very homogeneous tumors consisting only of Schwann cells. The tumor cells always stay on the outside of the nerve, but the tumor itself may either push the nerve aside and/or up against a bony structure (thereby possibly causing damage). Schwannomas are relatively slow growing. For reasons not yet understood, schwannomas are mostly benign and less than 1% become malignant (degenerate into cancer). This form of cancer is known as malignant peripheral nerve sheath tumour or malignant Schwannoma or neurofibrosarcoma.

Schwannomas can arise from a genetic disorder called schwannomatosis.

See also

• Neurofibroma
• Vestibular schwannoma (Acoustic neuroma)