Laparoscopic resection of ancient schwannoma embedded in the psoas muscle.

Schwannoma is a tumor originating from the Schwann cell of the peripheral nerve sheath. The diagnosis of schwannoma is based on histologic analysis of surgically excised sample. Retroperitoneal ancient schwannoma, a variant of schwannoma, is rarely observed in clinical practice. We report the case of a 46-year-old man with a retroperitoneal tumor embedded in the psoas muscle, which was treated by laparoscopic resection. The operative result was good, and pathologic analysis revealed a 5.5 × 4.5 cm ancient schwannoma.