A Case of Gallbladder Cancer Associated with Pancreaticobiliary Maljunction

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We report a case of gallbladder cancer associated with pancreaticobiliary maljunction. The patient was a 60-year-old woman who consulted a local doctor because of discomfort in the right hypochondriac region. Abdominal ultrasonography (US) showed a gallbladder abnormality, and she was referred to Kurume University Hospital, where she was hospitalized for further study and surgery. Abdominal US revealed a sessile tumor with an irregular surface in the fundus of the gallbladder. The internal echo of the tumor was nonhomogeneous, and the structure of the gallbladder wall was partly torn. The common bile duct and the left intrahepatic bile duct were dilated. Abdominal computed tomography (CT) showed an elevated lesion with the same degree of imaging effect as that of the liver on the peritoneal side of the fundus of the gallbladder. The structure of the gallbladder was preserved, and the gallbladder was well demarcated from the surrounding tissue. No hepatic or lymph node metastases were noted. Endoscopic retrograde cholangiopancreatography (ERCP) visualized the pancreaticobiliary maljunction where the pancreatic duct joined the bile duct, entering an approximately 2-cm-long common channel. Dilatation of the common bile duct and intrahepatic bile ducts was observed and diagnosed as the IV-A type according to the Toya classification. Abdominal angiography in the arterial phase showed dilatation of the cystic artery and hyperplasia of vessels but no apparent encasement. In the venous phase, a deep-staining tumor was observed. From the above findings, we made a diagnosis of gallbladder cancer complicating pancreaticobiliary maljunction, and performed an operation. Since intraoperative US showed that the outermost layer of the gallbladder was in part ill-demarcated, we diagnosed the depth of penetration as ss, and performed cholecystectomy and bile duct resection and hepatic resection (S4a and S5), and lymphnode dissection (D₂; dissection of groups 1 and 2 lymphnodes). The resected specimen grossly showed a papillomatous lesion with a cauliflower-like surface. The histopathologic diagnosis was papillary adenocarcinoma, depth ss, stage II. Tumor cells proliferated in a papillomatous pattern and were mostly confined to the muscular coat but partly infiltrated into the subserosal coat. In the diagnosis of pancreaticobiliary maljunction, it is crucial to consider complicating gallbladder cancer.