[A case of so-called carcinosarcoma of the middle portion of the bile duct diagnosed preoperatively].

A 73-year-old man was admitted to a hospital with a complaint of epigastralgia and for evaluation of liver dysfunction. After hospitalization, he experienced disturbance of consciousness with septic shock, and was then transferred to our hospital. Computed tomography revealed dilatation of the intrahepatic bile duct and tumor of the middle bile duct. We diagnosed acute obstructive suppurative cholangitis. As a result, endoscopic nasobiliary drainage was performed, and the patient recovered. Based on pathological examinations of the bile duct biopsy specimen, the tumor was diagnosed as a carcinosarcoma. Consequently, the patient underwent pylorus-preserving pancreatoduodenectomy. However, 4 months after surgery, the patient died due to widespread metastasis of the carcinosarcoma. Preoperative diagnosis of carcinosarcoma of the bile duct is extremely rare. Our study suggests the efficacy of bile duct biopsy in such cases.