Rare Portal Venous Anomaly in a Living Liver Donor: A Case Report

Knowledge of the anatomy of the portal system is essential for safe liver resection. We report a very rare anatomic anomaly of the portal system in a living liver donor. A 24-year-old female living liver donor was found to have anomalies of the portal system on preoperative contrast-enhanced computed tomography. The ventral branch of the right anterior segment arose from the transverse portion of the left portal vein. The gallbladder and round ligament were positioned normally. Intraoperative cholangiography for evaluation of biliary anatomy revealed very low confluence of the right and left hepatic ducts. All the bile ducts from the right lobe merged into the right hepatic duct. A right lobe graft was performed, including the ventral area of the right anterior segment. The portal branch of the ventral area of the right anterior segment could be transected extrahepatically. In the recipient operation, each of the right main portal branches, including the right posterior segment branch and the dorsal branch of the right anterior segment, and the ventral branch of the right anterior segment, were anastomosed to the right and left branches of the portal vein, respectively, of the recipient. The transected right hepatic duct of the graft was anastomosed with the recipient's common hepatic duct. Sixteen years after the liver transplant, the recipient continues to do well and has good portal flow.