Novel insights into the intraepithelial spread of extrahepatic cholangiocarcinoma: clinicopathological study of 382 cases on extrahepatic cholangiocarcinoma

Background Extrahepatic cholangiocarcinoma (eCCA) is a rare and aggressive disease consisted of conventional eCCA intraductal papillary neoplasm the bile duct (IPNB). Intraepithelial spread (IES) cancer cells beyond invasive area often observed in IPNBs; however, prevalence IES remains to be examined eCCAs. Here, we evaluated clinicopathological features eCCAs according tumor location, with focus on presence IES. The extension was also compared among biliary tract cancers (BTCs). Methods We significance (n=382) BTCs, including gallbladder (n=172), cystic (n=20), ampullary (n=102). Results Among eCCAs, IPNB had higher rate (89.2%) than (57.0%). distal (75.4%) significantly perihilar (41.3%). associated survival patients ( P =0.030). Extension into (CyD) that reached junction CyD favorable prognostic factor <0.001). association IES, either extrahepatic or CyD, differed depending location type eCCA. properties were dependent different types tumors BTCs; usually, incidence became 50% tissues developed, whereas other decreased incidence. Conclusion Thus, have characteristics type.