Bellini duct (collecting duct) carcinoma of the kidney is a rare entit
y often misinterpreted as renal or transitional cell carcinoma on hist
ologic examination. Immunohistochemical identification of specific ant
igens is needed for the differential diagnosis. We describe a case of
Bellini duct carcinoma that arose from the collecting ducts of Bellini
and was treated with aggressive surgery and interferon-based immunoch
emotherapy.