A case of small cell carcinoma of the common bile duct

Small cell carcinoma occasionally occurs in the gastrointestinal tract, but rarely in the biliary tract. We report a case of small cell carcinoma which occurred in the common bile duct. A 66-year-old female complained of epigastralgia and weight loss. Computed tomography and ultrasonography showed a mass near the pancreas head and dilatation of the intrahepatic bile ducts. Endoscopic nasobiliary drainage was undertaken, and it revealed obstruction of the common bile duct. The patient was diagnosed preoperatively as having extrahepatic bile duct cancer. Upon laparotomy, a tumor was found to be located in the middle common bile duct. Pylorus-preserving pancreaticoduodenectomy was performed. The main trunk of the portal vein and the right hepatic artery were resected concomitantly because of tumor involvement. Postoperative pathological examination revealed well-differentiated papillary adenocarcinoma on the surface of the bile duct lumen, but a large part of the extraductal component was small cell carcinoma. Upon immunohistochemical examination, synaptophysin and chromogranin A were found to be focally positive in small cell carcinoma, but negative for L-26 and CEA. The patient then underwent two postoperative courses of systemic chemotherapy. Nevertheless, she died of cancer recurrence eight months after the operation, which showed that the tumor had a highly lethal nature, with rapid and widespread dissemination. Further therapeutic trials are needed to improve survival in such cases.