Abstract
There are a group of biliary tumors showing intraductal papillary growth of neoplastic biliary epithelial cells with mucin overproduction and luminal dilatation. This tumor entity includes intraductal growth type of intrahepatic cholangiocarcinoma, biliary papillomatosis and biliary cystadenoma/adenocarcinoma showing communication with bile duct. Because these tumors resemble intraductal papillary mucinous neoplasm of pancreas, a collective term“intraductal papillary neoplasm of bile duct (IPNB)”was proposed for them. IPNB arises in the intrahepatic large bile duct, hepatic ducts and extrahepatic bile ducts, and shows histologically welldifferentiated adenocarcinoma, borderline lesion, and low grade malignancy. IPNB shows focal invasion, and some of advanced cholangiocarcinoma might be derived from IPNB. We propose here IPNB as a new disease entity, and new therapy should be developed against IPNB.
