胆管内腫瘍栓を認め，原発性肝内胆管癌との鑑別を要した異時性大腸癌肝転移の1切除例

The patient was a 68-year-old man who had undergone right hemicolectomy for ascending colon cancer, and pulmonary resection for lung metastases. After 10 months of operations, abdominal computed tomograms revealed a liver tumor with a biliary tumor thrombus in the segment 5 and a localized dilation of the intrahepatic bile duct. Endoscopic retrograde cholangiopancreatography showed obstruction, 2cm long, of the intrahepatic bile duct （B5） and dilation of the peripheral duct. Cytological examination of extracted bile showed adenocarcinoma. A right hepatic lobectomy was performed under the diagnosis of metastatic liver tumor with tumor development in the intrahepatic bile duct or intrahepatic cholangiocarcinoma. The resected specimen showed massive infiltration of the tumor into intrahepatic bile duct （B5） with forming a tumor thrombus. Histologically, the tumor was moderately differentiated adenocarcinoma, similar to the ascending colon cancer. The final diagnosis was liver metastasis of ascending colon cancer with intrabiliary tumor growth.