Intraductal Papillary Neoplasm of Bile Duct : Terminology

Terminology: Neoplasms currently known as intraductal papillary neoplasms of the bile duct (IPNB) have been previously referred to by a variety of names, including papillary (or villous) adenoma, papilloma, papillomatosis, and papillary adenocarcinoma. Tumors that produced copious mucin were called mucin-producing cholangiocarcinoma, mucin-hypersecreting bile duct tumor, and intraductal papillary mucinous tumor of the bile duct. They were considered biliary counterpart of intraductal papillary mucinous neoplasm (IPMN) of the pancreas. If IPNB shows stromal invasion, it is designated as IPNB with associated invasive carcinoma.

Pathologists from Japan and Korea have proposed a classification scheme that divides IPNBs into type 1 and type 2. They are discussed further with microscopic features. This image shows an IPNB growing within the lumen of common bile duct. Note the papillary architecture. Pancreas is seen at the bottom.