Ancient retroperitoneal schwannoma: A case report.

Schwannoma is a tumor of soft tissue originating from Schwann cells which rarely appears in the retroperitoneum region. The retroperitoneal schwannoma can grow to a large size slowly without any specific clinical sign or symptoms. We report a 35-year-old woman with ancient schwannoma complaining abdominal pain for three years, which was initially judged as urinary tract infection. Following imaging studies, retroperitoneal mass was found and judged as benign lesion. Partial excision of the tumor was performed, with histology examination showed degenerative changes that was consistent with ancient schwannoma. No evidence of recurrence appeared during follow-up period.