A novel anatomic variation of the intrahepatic biliary tree in live liver donor surgery: A case report

INTRODUCTION: Anatomic variations of the biliary tree are common, making precise anatomic evaluation important before hepatobiliary surgery. PRESENTATION OF CASE: A 52-year-old woman with no medical history was admitted to our hospital for a live-liver donation to her husband. During her evaluation, magnetic resonance cholangiopancreatography (MRCP) revealed a previously unknown anatomic variation in her biliary system. Segment 2 of the bile duct (B2) independently drained into the posterior branch and formed a common channel (B2+posterior) before joining the anterior branch. Then, bile duct segments 3 and 4 (B3+4) drained into this B2+posterior+anterior channel to form a common hepatic duct. The computerized overlay features shown by MRCP and three-dimensional computed tomography clarified this anatomic variation. A right lobe donor graft was then obtained successfully, with intraoperative cholangiography confirming that the donated graft had two bile duct orifices (i.e., posterior and anterior branches). We thus avoided surgical missteps that would have disallowed bile drainage of B2 and B3+4 into the common hepatic duct. DISCUSSION: Precise evaluation is mandatory for hepatobiliary surgical planning to rule out, or discover, challenging bile duct anatomy. CONCLUSION: Preoperative computerized overlay visualization of MRCP and computed tomography allowed definition of a previously unknown biliary tree variation.