ABSTRACT
<p>Liver metastases from colorectal carcinoma commonly form nodular lesions in the liverparenchyma. We report a case of liver metastasis from rectal adenocarcinoma that extendedpredominantly into the bile duct. A 62-year-old Japanese man underwent low anteriorresection for rectal adenocarcinoma 9 years ago. Approximately 3 years later, he underwentradiofrequency ablation therapy for a metastatic liver tumor. Nine years after surgery, atumor in liver segment III exhibiting intrabiliary extension was discovered; it wasunclear if this was a metastatic liver tumor or intrahepatic cholangiocarcinoma.Accordingly, we performed a left hepatectomy with lymph node dissection. The tumor wasnegative for cytokeratins 7 and 20, and was histologically similar to the primary rectaladenocarcinoma; it was diagnosed as rectal carcinoma metastasis. The patient has survivedfor 3 years after the hepatic surgery, for 9 years after radiofrequency ablation therapy,and for 12 years after the primary surgery. This case shows that liver metastasis fromcolorectal carcinoma can present as a predominantly intrabiliary growth that mimicsintrahepatic cholangiocarcinoma on imaging. Moreover, our case provides evidence for thesuperiority of anatomical hepatectomy over partial hepatectomy for metastatic liver tumorswith intrabiliary growth arising from rectal adenocarcinomas.</p>