- Cytologically or histologically confirmed. In case of uncertain biliary tract origin (e.g., intrahepatic, peripheral cholangiocarcinomas), inclusion is possible if i) extensive search for primary (thoracic and abdominopelvic CT scan, colonoscopy, upper digestive endoscopy, serum PSA level for men or mammography for women, and FDG-PET if possible) is negative; and ii) histological examination is consistent with bile duct adenocarcinoma (IHC should ideally be performed and be consistent with biliary primary, e.g., positive for cytokeratin 7 and 19 and negative for cytokeratin 20).