Distal nephron carcinoma: a rare kidney tumor.

Bellini's duct carcinoma is a very rare tumor originating from the collecting tubules of the kidney. It should be part of differential diagnosis in cases with gross hematuria, failed diagnostic proof of a tumor within the collecting system and a centrally located hypovascular mass. Analysis of the cytoskeleton by means of cytokeratin patterns enables classification as a tumor of urothelial origin.