Pathology of Cholangiocarcinoma.

The liver excretes bile through the biliary system, which has a complicated anatomical structure. Cholangiocarcinoma, a malignant bile duct epithelial tumor, is separated into intrahepatic and extrahepatic portions depending on the structure of the bile duct and exhibits both similarities and varieties in patient presentations and staging. The three main macroscopic characteristics of cholangiocarcinoma-mass formating, intraductal growth, and periductal infiltrating types-allow pathologists and surgeons to see and analyze the cancerous tissue. The majority of cholangiocarcinoma patients are in advanced stages and poor prognosis. Although surgery is the main treatment option, target therapy based on molecular pathology background offers hope for improving patient's prognosis.