Hepatectomy for Hilar Cholangiocarcinoma with Right-Sided Ligamentum Teres Using a Hepatectomy Simulation System.

Right-sided ligamentum teres (RSLT) is a rare congenital anomaly often accompanied by variation of the hepatic vasculature. We herein report a surgical case of a hilar cholangiocarcinoma with RSLT in whom preoperative hepatectomy simulation proved useful for understanding the anatomical structure of the liver. A 78-year-old male with obstructive jaundice was referred to our department for further examination. The patient was suspected of having a hilar cholangiocarcinoma originating from the left hepatic bile duct by contrast-enhanced computed tomography (CT), and CT also showed right umbilical portion (RUP). Three-dimensional images of the hepatic vasculature and biliary system reconstructed using a hepatectomy simulation system suggested that all portal branches ramified from RUP were right paramedian branches, and three leftward portal branches from these ran parallel to the peripheral bile ducts confluent with the left hepatic bile duct, where the tumor was present. Hepatic resection of part of the ventral area of the right paramedian sector and left hemiliver was performed along the demarcation line drawn after clamping the portal branches; the ratio of estimated liver resection volume was 28.9%. After the operation, bile leakage occurred. However, the leakage was treated with percutaneous drainage alone, and the patient was discharged 77 days after the operation. The patient is doing well without any signs of recurrence 21 months after the operation. The vascular and biliary anatomy in patients with RSLT is complicated and should be evaluated in detail preoperatively using a hepatectomy simulation system.