Surgery is the preferred treatment for bile duct hamartomas.

Bile duct hamartoma (BDH) is a rare liver disease with a rising incidence in recent years. A retrospective study on BDH patients between June 2007 and December 2015 was conducted. All the medical records, including clinical, imaging and pathological characteristics, were retrieved. Follow-up data were obtained by telephone communication. The majority of the patients had no symptoms and the laboratory tests were normal. The appearance on ultrasound examination was variable. The lesion exhibited low density on plain computed tomography and no enhancement in 4 cases, and inhomogeneous enhancement in 1 case. Magnetic resonance imaging examination revealed hypointensity on T1-weighted imaging (WI), hyperintensity on T2WI, no enhancement in 1 case, and enhancement in 4 cases. Two patients underwent magnetic resonance cholangiopancreatography due to jaundice and intrahepatic bile duct dilation. The preoperative diagnosis was liver cancer in 4 cases, hepatic hilar biliary obstruction in 1, chronic calculous cholecystitis in 1, suspected hepatic abscess in 1, and benign liver tumor in 2 cases. All the patients underwent surgery. Nest-like cell arrangements were observed in 2 patients, and in 1 patient the lesion transformed to intrahepatic cholangiocarcinoma, resulting in the patient's death 25 months after surgery. Thus, BDH may transform into a life-threatening cholangiocarcinoma and it should be surgically removed. Furthermore, the mechanism underlying carcinogenesis in BDH requires further investigation.