Four branching patterns of intrahepatic biliary tree in cases with right sided ligamentum teres

Right-sided ligamentum teres (RSLT) is a rare entity whose incidence is reported to be 0.2 – 1.2%. The embryologic origin of this anomaly is the connection of the right fetal umbilical vein to the portal system. Although the vascular architecture has been well studied by Nagai, Shindo and their colleagues, there has been no systematic study of intrahepatic biliary anatomy of RSLT. We conducted a survey on the consecutive 4021 patients who received magnetic resonance cholangiopancreatography (MRCP) in our institute from January 2006 to August 2015, and found 13 cases with RSLT (0.3%). The following four branching patterns were identified. Surgeons should recognize these variations to avoid serious biliary injury in major hepatectomy of livers with RSLT. A) Six out of the 13 RSLT cases had apparently normal right and left hepatic ducts. The ventral branch of the right paramedian sector drained into the left hepatic duct. B) One case had an independent right lateral biliary branch. Bile ducts from the paramedian and left lateral sectors formed a common trunk on the left side of the right umbilical portion (UP). C) Five cases had a single common hepatic duct on the left side of the UP. The right lateral biliary branch formed an inverted C shape. D) One case had a single common hepatic duct on the right side of the UP. [biliary tree in RSLT]