Osseous metaplasia in renal cell carcinoma: report of a rare case.

Focal calcifications are frequently seen in renal masses including renal cell carcinoma (RCC). Osseous metaplasia, on the other hand, is a rare finding in RCC. We report a case of RCC with radiological evidence of speckled calcification that showed osseous metaplasia on histopathological examination. The clinical and pathologic differential diagnosis for this tumor is discussed along with a review of the literature on this unusual phenomenon.