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 aggressive primary renal neoplasm. The coexistence of two synchronous neoplasms in the same kidney is highly infrequent. As a result, it is hardly surprising that there are no references to renal cell carcinoma (RCC) combined with CDC of the same kidney in the literature. Histology and immunohistochemistry are important tools for differentiating between the two types of tumors involved. We present the first case of a synchronous occurrence of RCC and CDC of the same kidney.