A case of metachronous intraductal tubulopapillary carcinoma of the pancreas after surgery for gallbladder cancer-accompanied pancreaticobiliary maljunction

Herein, we report an extremely rare case of intraductal tubulopapillary carcinoma (ITPC) that was detected due to the pancreatic duct dilatation newly appeared on CT after surgery for gallbladder cancer associated with pancreaticobiliary maljunction. Present case: a 77-year-old female. Extended cholecystectomy, extra-bile duct resection, and hepaticojejunostomy was performed and resected specimen showed that this gallbladder tumor was papillary adenocarcinoma, pT2(ss), pN0, pDM0, pHM0, pEM0. Thereafter, the follow-up CT scan 2 years after surgery detected the dilatation of main pancreatic duct (MPD) and the elevation of carcinoembryonic antigen (CEA) level was pointed out (4.9 to 5.9 ng/ml). Moreover, pancreatic juice cytology revealed adenocarcinoma cells. Thus, distal pancreatectomy was performed based on the diagnosis of pancreatic adenocarcinoma associated with pancreaticobiliary maljunction (PBM). Histologically, proliferation of highly columnar atypical cells in the dilated main pancreatic duct with marked papillary and irregular tubular structures is seen. No mucus production is observed. Based on immunohistochemistry, Mucin (MUC) 1, 2 and 5AC were focal weak positive, negative and negative, respectively. Taken together of these findings, we could diagnose this tumor with ITPC without invasive component. The patient is alive without any recurrence for 36 months after a second surgery. In conclusion, it is essential to be fully aware that PBM is a disease in which there is still a possibility that pancreatic or biliary tract cancer may occur in the future, and that careful routine follow-up for a long period after diversion surgery may lead to early detection of complicated cancers.