OBJECTIVES: The aim of this study was to compare imaging and pathological results of congenital cystic enlargement of the biliary tract to determine the best preoperative management strategy. PATIENTS AND METHODS: Radiological findings of 14 cases treated by surgery were reviewed. Radiological examinations were reviewed: ultrasound (n = 20), computed tomography (n = 13), endoscopic ultrasound (n = 8), endoscopic retrograde cholangiopancreatography (n = 10), percutaneous transhepatic cholangiography (n = 3), peroperative cholangiography (n = 11). Imaging and surgical or pathological correlations were obtained with regard to topographical type using Todani's classification, pancreatobiliary junction, and associated diseases, especially biliary malignancies (cystic wall and gallbladder). RESULTS: Cystic enlargement of the biliary tract was type Ia in 2 patients, type Ib in 1, type Ic in 4, type IVa in 5, and type IVb in 2. The radio-pathological correlation was excellent for the topographical type, and quite good for intrahepatic extension. An abnormal pancreatobiliary junction was identified in 5 cases, and visualized before surgery in I case. This junction was not opacified pre- or pre-operatively in 7 cases. Gallbladder stones were present in 2 cases, choledocal stones, in 2 cases, and intrahepatic stones in one cases, always seen on ultrasound. Malignant degeneration was present in the cyst in one case in the pathological specimen, but was not visualized by imaging procedures or peroperatively; one intrahepatic degeneration was visualized on CT and histologically proven in the surgical specimen. CONCLUSION: Ultrasound and CT allow positive diagnosis of cystic enlargement of the biliary tract, and diagnosis of intrahepatic cyst and associated diseases. The bifurcation extension and the study of pancreatobiliary junction require peroperative or retrograde cholangiography.