Collision tumor of kidney: A case of renal cell carcinoma with metastases of prostatic adenocarcinoma

Simultaneous occurrence of prostatic adenocarcinoma and renal cell carcinoma is well documented in the literature. However, metastatic prostatic adenocarcinoma in a kidney harboring a renal cell carcinoma (RCC) is quite rare. Although renal cell carcinoma is the most common tumor that can harbor metastasis, metastatic prostatic adenocarcinoma in a kidney harboring a RCC is quite rare. There are four cases in the literature showing metastasis of prostatic adenocarcinoma to RCC. However, as per our knowledge, this is the first case of a collision between RCC and metastatic prostatic adenocarcinoma.