Primary synovial sarcoma of the kidney.

Primary renal synovial sarcomas (SS) are rare tumors of the kidney. Faria first described primary renal synovial sarcoma in 1999. Twenty-one cases of primary renal synovial sarcoma have been reported to date. Primary renal synovial sarcomas can exist in either a monophasic or a biphasic pattern. The monophasic variant of primary renal synovial sarcoma is more common and tends to have a better prognosis than the biphasic variant. We present the case of a 61 year-old woman with a monophasic variant of primary renal synovial sarcoma.