Dilatation of the intrahepatic bile ducts associated with benign liver lesions: an unusual finding

In three patients presenting different types of liver lesions, including isolated cyst, focal nodular hyperplasia (FNH), and hemangioma, intrahepatic bile duct dilatation was observed on US and CT. Final diagnosis was obtained by surgery in two cases (cyst and FNH) and by 1-year follow-up in one patient presenting an isolated hemangioma. The only common characteristic in our three cases was that lesions were present in segment four according to Couinaud's classification, at the level of the transverse fissure, suggesting that a space-occupying lesion at this site may cause compression of the common hepatic duct and right or left intrahepatic bile ducts. Our report indicates that compression may occur even with lesion of moderate size (35-40 mm in diameter). A benign liver lesion may cause a bile duct dilatation, particularly if located in segment 4, close to the hilum. Awareness of this possibility is important to avoid unnecessary invasive diagnostic procedures, particularly when all imaging criteria are consistent with a benign lesion.