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 foc...
