ABSTRACT
Biliary papilloma usually consists of single or multiple papillary adenomas in the biliary tract and has a potential for recurrence and malignant transformation. We described herein a case of papillary adenoma of intrahepatic duct that transformed into papillary adenocarcinoma. A 49-year-old male patient was admitted to our hospital because of right upper quadrant pain. A CT scan revealed marked dilatation of S7 segmental duct and cholangioscopy and biopsy revealed mucin-secreting papillary adenoma in the right intrahepatic duct. Three years later, a follow up of CT scan showed aggravated S7 ductal dilatation and inner ill-defined mass. Cholangioscopy revealed multiple papillary mucosal projections with large amount of mucin in the right intrahepatic duct and biopsy revealed well differentiated papillary adenocarcinoma. The patient underwent right lobectomy, the papillary adenocarcinoma was extended in the dilated right intrahepatic duct and also showed hepatic parenchymal invasion.