Cholangiocarcinoma arising in bile duct adenoma with focal area of bile duct hamartoma

A 59-year-old male with history of sigmoid colon cancer had a high serum-CEA level and was referred for the evaluation of metastatic liver disease. Ultrasonography and computerized tomography showed two tumours in the liver. Macroscopically, these were in segment 4 (S4) and 2 (S2). Histologically, the tumour in S4 showed a number of bile ductules with variable amounts of stroma, an appearance compatible with bile duct adenoma (BDA). There were markedly atypical ductules of various sizes, the epithelium of which had coarsely granular/hyperchromatic large nuclei, in some areas of the lesion. These atypical ductules showed invasive growth into the liver parenchyma. Some cystically dilated ductules with bile plugs resembling bile duct hamartoma (BDH) were also seen. The other tumour in S2, was a metastatic adenocarcinoma from sigmoid colon and showed strongly positive staining for CEA. Since the lesion in S4 of our case is solitary and most of histological features are similar to those of BDA with markedly atypical bile ductules, we consider that this may be the first case of cholangiocarcinoma associated with BDA with focal area of BDH. It is possible that the adenoma-carcinoma sequence occurs in biliary tumours.