Metachronous intraductal papillary mucinous carcinoma five years after cholecystectomy for gallbladder cancer in a patient with pancreaticobiliary maljunction

A 71-year-old female with non-dilated pancreaticobiliary maljunction (PBM) and gallbladder polypoid lesions underwent laparoscopic cholecystectomy. Histological examination of the polypoid lesions revealed gallbladder cancer. Five years after cholecystectomy, gradual dilatation of the main pancreatic duct (MPD) led to the identification of a papillary tumor growing in the MPD of the pancreatic head. Subtotal stomach-preserving pancreaticoduodenectomy was performed. Pathological examination revealed a papillary tumor with focal invasion to the MPD. Immunohistochemically, the tumor cells were positive for MUC1 and MUC5AC and negative for MUC2. Therefore, the definitive diagnosis was pancreatobiliary-type intraductal papillary mucinous carcinoma. This case emphasizes the significance of surveillance for potential cancer of the pancreas as well as the biliary tract in patients with PBM.