Gallbladder Cancer with Biliary Intraepithelial Neoplasia Complicated by Pancreaticobiliary Maljunction: A Case Report

We report herein a case of gallbladder cancer with biliary intraepithelial neoplasia (BilIN) complicated by pancreaticobiliary maljunction (PBM). A 60-year-old woman was referred to our hospital for thickening of the gallbladder wall diagnosed via ultrasonography at the referring clinic. The Radiographic images showed thickening of the gallbladder wall and a high confluence of pancreaticobiliary ducts outside the duodenal wall without dilatation of the bile duct. The amylase level in the bile duct was highly elevated. The patient was initially diagnosed with PBM without biliary dilatation, and laparoscopic cholecystectomy was performed. Histopathology of the resected specimen revealed gallbladder cancer localized in the mucosa propria with widespread BilIN. Immunohistochemical analyses showed positive results for S100P,IMP3 and p16ink4a in tumor cells, but a positive result for only IMP3 in adenocarcinoma. Expression of p53 was negative. Oncogenic KRAS mutations were not detected in tumor cells. The patient was diagnosed with gallbladder cancer with BilIN complicated by PBM. This case report may be useful in clarifying the carcinogenic process and genetic mutations for gallbladder cancer associated with PBM.