NCI: A rare type of kidney cancer that grows and spreads quickly. It begins in the duct of Bellini in the kidney.,NCI: A recently described type of renal carcinoma, affecting mostly young African-Americans. It is located in the medulla of the kidney, and follows an aggressive clinical course. Most reported cases have shown metastatic disease at the time of diagnosis.,NCI: Also known as collecting duct carcinoma, this is a rare type of renal carcinoma. It arises from the collecting ducts of the renal medulla, and most authors suggest that this is an aggressive tumor.