Undifferentiated carcinoma of the common bile duct with intraductal tumor thrombi: report of a case.

We report a case of undifferentiated carcinoma of the common bile duct with intraductal tumor thrombi. A 73-year-old man presented with general malaise. Abdominal computed tomography and magnetic resonance imaging revealed a mass in the distal common bile duct, accompanied by dilatation of the intra- and extrahepatic bile ducts. The patient underwent pancreaticoduodenectomy with regional lymphadenectomy. Gross examination revealed that the distal common bile duct was obstructed by an elastic hard mass, 3.2 × 2.6 cm, accompanied by intraductal tumor thrombi. Microscopically, the nodule was well defined and composed of atypical large tumor cells with bizarre nuclei and little cytoplasm. Immunohistochemically, the tumor cells were diffusely positive for cytokeratin-7 and CAM5.2, but negative for CD56, chromogranin A, and synaptophysin. Thus, a histological diagnosis of undifferentiated carcinoma of the common bile duct was made. The patient recovered uneventfully and has remained free of any signs of recurrence for 18 months since the operation. Undifferentiated carcinomas of the extrahepatic bile duct can be detected early, with the chance of a good prognosis; however, because their biologic growth behavior is still considered aggressive, careful observation after surgery and the initiation of multidisciplinary treatment against recurrence are necessary.