Angiosarcoma of the kidney with minute clear cell carcinomas: a case report.

A case of renal angiosarcoma with minute clear cell carcinomas in a 61-year-old male is described. The tumor was clinically considered a renal cell carcinoma. The lesion, removed by nephrectomy, was an unencapsulated hemorrhagic mass measuring 8.0cm in diameter. The tumor was histologically characterized by anastomosing vascular channels lined by cytologically atypical endothelial cells. The tumor cells reacted positively with CD31, factor-VIII related antigen, and CD34. A few minute clear cell carcinomas measuring less than 1mm were observed in the periphery of the angiosarcoma. There was no transition between angiosarcoma and renal cell carcinoma. The patient died of a widespread disease 13 months after surgery. This tumor is considered a primary renal angiosarcoma with clear cell carcinomas and not a sarcomatoid carcinoma.