Accessory right hepatic artery and aberrant bile duct in the hepatocystic triangle: a rare case with clinical implications

Awareness of variations in the hepatic vasculature and biliary system is extremely important for avoiding iatrogenic injury in upper-abdominal surgery. The objective of this study is to describe a rare case of abnormal vascular and biliary structures in the hepatocystic triangle (HCT) (the modern Calot's triangle). During anatomical dissection of the coeliac trunk (CT) in an old man, the authors observed the presence of a hepatosplenic trunk arising from the CT and bifurcating into common hepatic and splenic arteries. The common hepatic artery divided into hepatic artery proper and gastroduodenal artery. The presence of accessory right hepatic artery (ARHA) arising from the superior mesenteric artery was also notable. The aberrant artery ascended retropancreatically ventral to the splenic vein, then posterolaterally to the portal vein before termination into the right hepatic lobe in the HCT. Within this triangle, there was an aberrant bile duct originating in the right hepatic lobe and ending in the common hepatic duct. This accessory duct crossed the ARHA and an associated branch (the cystic artery). There is no known previous report on the co-existence of an ARHA and an aberrant bile duct within the HCT, in addition to the hepatosplenic trunk. The clinical implications of the current case are addressed in discussion.