[A Case Report of Pancreatic Adenosquamous Carcinoma in a Patient with Pancreaticobiliary Maljunction].

We report a rare case of pancreatic adenosquamous carcinoma(PASC)associated with pancreaticobiliary maljunction (PBM). An elderly woman in her 80s presented with epigastric pain and anorexia. CT revealed a mass at the distal bile duct and pancreatic head, with a nodular lesion in the gallbladder fundus. Endoscopic retrograde cholangiopancreatography (ERCP)revealed a distal bile duct stricture and a common channel between the pancreatic and bile ducts, suggesting distal cholangiocarcinoma or pancreatic cancer with PBM. PET-CT demonstrated FDG accumulation around the distal bile duct- pancreatic head region and the gallbladder fundus, raising the possibility of synchronous double cancer. She underwent subtotal stomach-preserving pancreaticoduodenectomy(SSPPD)with gallbladder bed, portal vein(PV), and right hepatic artery (RHA)resection. Pathology confirmed pancreatic adenosquamous carcinoma(Stage ⅡB)and gallbladder carcinoma(Stage ⅢB). Postoperative pancreatic fistula occurred, but she was discharged on postoperative day 35. Despite initial recovery, she developed multiple liver metastases and peritoneal dissemination, and died 6 months later. While PBM is known to increase the risk of biliary cancer, co-occurrence with PASC is extremely rare. We report this case with a literature review.