Are IPMN of the Pancreas and the Bile Duct Really the Same Disease?

초록

The biliary tract and pancreas are adjacent to each other, with the common bile duct of the biliary tract and the pancreatic duct uniting at the ampulla of Vater. Both organs derive from the foregut at almost the same time, and recent animal studies have disclosed that they show plasticity to each other during development.1 Diseases of the biliary tract and pancreas have a similar pathophysiology.2,3 For example, advanced cholangiocarcinoma and preneoplastic or early intraepithelial neoplasms of the biliary tract show similar morphological or genetical changes to their pancreatic counterparts.4,5 These findings suggest that some biliary tract and pancreatic diseases develop via the same process and show similar morphology and phenotypes. Papillary‐type of biliary tumors with benign or borderline features and differing malignant features are currently identified by several pathological terms such as biliary papilloma (papillomatosis), papillary carcinoma of the bile duct, or intraductal growth type of cholangiocarcinoma (CC).6‐11 These biliary papillary tumors share clinicopathological features of pancreatic intraductal papillary mucin‐producing neoplasm (IPMN‐P). These cases are not infrequently associated with the overproduction or secretion of mucin. These papillary biliary tumors were collectively referred to as intraductal papillary neoplasm of the bile duct (IPNB) as a biliary counterpart of pancreatic IPMN.6,7 And it was only recently that the World Health Organization recognized IPNB as a distinct pathologic entity.12 In pathological characteristics and postoperative survival status, IPNB closely resembles pancreatic IPMN, suggesting that it’s the biliary counterpart of pancreatic IPMN. In this lecture, IPNB is discussed based on similarities to IPMN‐P.