Osteoclastoma-like giant cell tumor of the renal pelvis associated with papillary transitional cell carcinoma.

This report documents an uncommon case of osteoclastoma-like giant cell tumor of the renal pelvis associated with papillary transitional cell carcinoma, which resulted in the patient's death. A low-grade transitional papillary carcinoma associated with a prominent osteoclastoma-like giant cell tumor was found in the pelvicalyceal system of the right kidney in a 69-year-old man. The spindle component of the tumor stained for epithelial membrane antigen, indicating an epithelial origin. Positive staining with antibody against p53 protein was observed in both tumoral components. Our results suggest that this osteoclastoma-like giant cell tumor was truly neoplastic and that the two components could have arisen from an initial monoclonal neoplastic proliferation.