Primary renal sarcoma with morphologic and immunohistochemical aspects compatible with synovial sarcoma.

Primary synovial sarcoma of the kidney is a rare tumor that is difficult to diagnose. We present one case that was not diagnosed through fine needle aspiration, requiring a morphologic and immunohistochemical analysis of the incision biopsy. Since the tumor was surgically unresectable, chemotherapy was employed previously to definitive radical surgery.