Renal cell carcinoma associated with granulomatous reaction.

Granulomatous inflammation is a distinctive pattern of chronic inflammatory reaction characterized by accumulation of epithelioid histiocytes and multinucleate giant cells. The cause of granulomas can be infectious or non-infectious. Granulomas have been described within the stroma of malignancies like carcinomas of the breast and colon, seminoma and Hodgkin's lymphoma, where they represent T-cell-mediated reaction of the tumor stroma to antigens expressed by the tumor. Granulomatous reaction in association with renal cell carcinoma (RCC) is uncommon, with only few published reports in the literature. We describe three cases of conventional (clear cell) RCC associated with epithelioid granulomas within the tumor parenchyma.