Intraductal papillary neoplasms of the bile duct (IPNB) were defined by the WHO in 2010 as bile duct tumors. IPNB includes the previous categories of bile duct papilloma/papillomatosis, papillary carcinoma, and mucin-secreting bile duct tumors. Depending on the morphology of their papillary gland, two types of IPNB are described (Type 1 and Type 2 IPNB). Generally, IPNBs are found in every segment of the bile duct system but are more often located in the extrahepatic bile ducts (2:1 compared to the intrahepatic localization). Type 1 IPNBs show an intrahepatic or perihilar location, whereas Type 2 IPNBs are more frequently located in the distal bile duct. IPNBs are precursors of bile duct cancers according to the adenoma–carcinoma sequence, and therefore, surgical resection is indicated in most cases.