This is a report of a case of choledochal dilation in a 5-year-old boy associated with an aberrant hepatic bile duct draining the posterior segment of the right hepatic lobe. Episodes of repeated abdominal pain and vomiting brought him to our consultation. At laparotomy, 2 ductal structures, 3 mm in diameter each, were found at the uppermost aspect of the choledochal dilation, which was about the size of 4 × 3 × 3cm. Intraoperative cholangiograms revealed that the post-erior segment duct did not join its anterior counterpart, but terminated independently at the choledochal cyst. The anterior segment duct united witin the liver with the left hepatic duct and then entered the cyst just to the right of the posterior segment duct entry. Three hundred and nineteen cases of aberrant hepatic bile duct were collected from Japanese and English literatures and analysed. The anterior segment of the right hepatic lobe is the commonest site of origin for an aberrant hepatic bile duct, which comes from the right hepatic lobe in 96.9% of the cases. It is emphasized that intraoperative cholangiography should be so performed as attention be paid not only to the pancreaticobiliary ducts relationship, but to the anatomical communication between the intra-and the extrahepatic biliary systems. Identification of the anterior as well as the posterior segmental bile ducts of the right hepatic lobe is mandatory for an uncomplicated biliary reconstruction. The role of an aberrant hepatic bile duct in the pathogenesis of congenital choledochal dilation is doubtful as yet from embryological point of view and remains to he further studied.
