Left hepatic trisectionectomy for perihilar cholangiocarcinoma with a right-sided round ligament: A case report

BACKGROUND: A right-sided round ligament (RSRL) is a rare, congenital anomaly of the intrahepatic portal vein, with a reported frequency of 0.2%-1.2%. For patients with perihilar cholangiocarcinoma associated with an RSRL, an accurate understanding of the vascular and biliary anatomy is indispensable. CASE SUMMARY: We report a 70-year-old male with perihilar cholangiocarcinoma associated with an RSRL. After percutaneous transhepatic embolization of the left and anterior portal branches, we conducted a left trisectionectomy of the liver with extrahepatic bile duct resection and hepaticojejunostomy. The postoperative course was uneventful, and R0 resection was achieved. When the liver volume of each section was compared between 7 patients with an RSRL and 20 patients with normal portal vein anatomy, the posterior section in RSRL patients was significantly larger than that in patients with normal portal vein anatomy (median: 457 mL vs 306 mL, P = 0.031). In patients with perihilar cholangiocarcinoma associated with an RSRL, left trisectionectomy has several surgical advantages: (1) The posterior branch of the portal vein often ramifies independently, and the division of the portal vein is easily conducted; (2) A relatively large amount of remnant liver can be retained; and (3) The anatomy of the posterior branch of the Glissonian pedicle is similar to that in patients with normal anatomy. CONCLUSION: In patients with an RSRL and perihilar cholangiocarcinoma that does not involve the posterior section, left trisectionectomy may be a favorable choice.