Synchronous ipsilateral renal tumors

Collision tumor is a phenomenon in which two histologically different tumors exist as distinct lesions within the same organ. Occurrence of two different, synchronous, and ipsilateral renal tumors is rare. We present a case of two synchronous tumors of kidney comprising of clear cell renal cell carcinoma [CCRCC] and chromophobe renal cell carcinoma [CRCC]. Grossly, two separate tumor nodules were identified with unremarkable intervening area. Microscopic examination from both tumor nodules revealed two different epithelial malignancies. It is prognostically significant as prognosis in such cases is determined by the more aggressive of the two tumors. In this case, CCRCC is more aggressive with a 5-year survival rate of 50-60 % as compared to CRCC with a 5-year survival rate of 80-90%