Rare renaissance: Quadruple synchronous renal cell tumors in one kidney - A case report.

Multifocality in renal tumors is a rare occurrence, but not unheard of. Commonly the different foci correspond to the same histological pathology, however co-existence with other renal lesions, including both malignant and benign tumors, have also been reported. Here we present a 57-year-old male, ex-smoker who exhibited four distinct histological tumors in an ipsilateral kidney; multilocular cystic clear cell renal cell carcinoma (RCC) of low malignant potential, clear cell papillary RCC, renal oncocytoma, and renomedullary interstitial cell tumor. To our knowledge this is the first time these four tumors were found in the same patient, let alone the same kidney.