Synchronus renal cell carcinoma and Bellini duct carcinoma: a case report on a rare coincidence

Bellini duct carcinoma or collecting duct carcinoma (CDC) is a rare but agg ressive primary renal neoplasm. The coexistence of two synchronous neoplasm s in the same kidney is highly infrequent. As a result, it is hardly surpri sing that there are no references to renal cell carcinoma (RCC) combined wi th CDC of the same kidney in the literature. Histology and immunohistochemi stry are important tools for differentiating between the two types of tumor s involved. We present the first case of a synchronous occurrence of RCC an d CDC of the same kidney.