A case of very large intrahepatic bile duct adenoma followed for 7 years

A 70-year-old man was referred to our hospital due to abnormal liver function. A tumor of 92 mm × 61 mm was detected on ultrasound screening of the left liver lobe. Although the tumor was suspected to be intrahepatic bile duct carcinoma, he had chronic heart disease and was unable to undergo surgery. Therefore, he was followed without further testing. No increase in tumor serum markers or tumor size was observed for the subsequent 7 years. We continued to suspect intrahepatic bile duct carcinoma, and we decided to perform a tumor biopsy. Tumor biopsy findings indicated intrahepatic bile duct adenoma (BDA), which is a rare benign epithelial liver tumor typically ranging from 1 mm to 20 mm. We herein report a case of very large BDA followed for 7 years.