Cholangiocarcinoma

Cholangiocarcinoma is a malignancy of the biliary epithelium. It is classified by location as intrahepatic, perihilar (at the hepatic duct confluence, also called hilar or Klatskin), or distal extrahepatic (closer to the duodenum and pancreatic head). Location predicts the first clinical problem: perihilar and distal tumours commonly narrow the main bile ducts, whereas an intrahepatic tumour may grow as a liver mass before obstructing major ducts. Bile normally carries conjugated bilirubin from hepatocytes into the intestine. When a tumour narrows that pathway, bilirubin backs up into the bloodstream and is excreted in urine rather than delivered to the gut. The result is jaundice, dark urine, reduced intestinal pigment with pale or acholic stools, and pruritus from retained bile constituents. Alkaline phosphatase (ALP) and gamma-glutamyl transferase (GGT) typically rise out of proportion to AST and ALT. This is a cholestatic pattern, not primarily a hepatocellular-injury pattern. An older adult with steadily worsening, relatively painless jaundice should be assessed for a distal biliary or pancreatic malignancy. It is a red flag, not a diagnosis: pancreatic-head cancer, benign postoperative or inflammatory strictures, choledocholithiasis,...