Schwannoma: a rare benign tumor of soft tissues.

'Schwannomas are unusual benign tumors which arise from the surface of neural elements of the body or within the brain. They do not as a rule metastasize but may cause sometimes severe local problems on the nerves, blood vessels and adjacent bone. The tumors arise from the Sheath of Schwann, a structure on the surface of a nerve. The lesions may expand and cause considerable damage to adjacent tissues. They do not arise within bone since there are no Sheaths of Schwann within the osseous tissue but may cause local damage to the bony cortex and sometimes fractures. Rarely the lesions may metastasize and cause patients' death. The treatment is usually local resection, and most often is successful although may cause damage to the adjacent nerve.