Dilated intrahepatic bile ducts without tumor‐induced obstruction were characteristic of occupational CCA and apparently corresponded to findings of PSC, including multiple intrahepatic bile duct strictures, with or without fusiform dilatation.13 Ultrasonography detected the occupational CCA in all 18 patients, which indicates that regular health examinations with a combination of ultrasonography and laboratory tests (including γ‐GGT, AST, ALT, CA19‐9, and CEA levels) can help screen for occupational CCA.12 CT, MRI, and MRCP can detect mass lesion and characteristic bile duct findings. This evidence concerns the gene CEACAM5 and cholangiocarcinoma.