[Giant tumor from the nerve sheath].

A schwannoma is a benign nerve sheath tumor derived from Schwann cells. They are usually small and solitary tumors more frequently localized in cranial nerves and the spinal cord and rarely in the limbs. Some cases have been reported involving extremities (mainly the upper ones) but with a small size. Cases of big size schwannomas unrelated to a neurofibromatosis are very rare. We report the case of a 25 year old patient, with a giant schwannoma which invaded the ischiatic region reaching the triceps surae.