A pelvic retroperitoneal Schwannoma presenting as an adnexal mass.

Solitary nerve sheath tumors such as benign schwannomas arising in the pelvic retroperitoneum are infrequently reported. We report a case of a benign retroperitoneal pelvic schwannoma that presented with pelvic pain and an adnexal mass. Complete surgical excision was achieved only after transection of the S1 nerve root on the left side. The adjacent vascular and urinary channels sustained no injuries and the patient had minimal neurologic deficit.