Renal Angiosarcoma

Primary Angiosarcoma of Kidney: This image shows a solid focus of high-grade angiosarcoma infiltrating the renal parenchyma. The tumor cells have epithelioid morphology with abundant eosinophilic cytoplasm and large vesicular nuclei with punctate nucleoli. Such cases would need a panel of immunohistochemical markers to differentiate them from various subtypes of renal cell carcinoma as well as metastases. Angiosarcomas are negative for epithelial markers like AE1/AE3, EMA, and CAM5.2, although focal positivity may be seen in a small percentage of cases with epithelioid morphology. They are also negative for RCC, CK8/18, CD10, S-100 protein, Melan-A, and HMB-45. On the other hand, they are positive for endothelial markers like CD31, CD34, FLI-1, Factor VIII-related antigen, and ERG.