Renal cell carcinoma containing fat mimicking angiomyolipoma: demonstration with CT scan and histopathology.

We report a case of a large renal tumour containing small amounts of fat and some calcification that proved to be a renal cell carcinoma. The CT appearance of the tumour was suggestive of an angiomyolipoma. Although the overwhelming majority of renal masses containing fat are angiomyolipomas, in the presence of calcification the diagnosis of renal cell carcinoma should be entertained.