A case of perihilar cholangiocarcinoma with bilateral ligamentum teres hepatis treated with hepatopancreatoduodenectomy.

BACKGROUND: Bilateral ligamentum teres (BLT) hepatis is a very rare anomaly defined as the connection of the bilateral fetal umbilical veins to both sides of the paramedian trunk, and it has never been reported in the English literature. CASE PRESENTATION: A 72-year-old man who presented with obstructive jaundice was referred to our hospital. Contrast-enhanced computed tomography revealed that the patient had right-sided ligamentum teres (RSLT) and left-sided ligamentum teres (LSLT). The umbilical portion of the left portal vein, which the LSLT connected, became relatively atrophic in this patient. The RSLT attached to the tip of the right anterior pedicle and formed the umbilical portion of the right portal vein. The patient was diagnosed with perihilar cholangiocarcinoma which had invaded the root of the posterior branch of the bile duct, LHD, and intrapancreatic bile duct. The central bisectionectomy, in which the liver parenchyma was resected along the RHV on the right side and the LSLT on the left side, and caudate lobectomy combined with pancreatoduodenectomy were performed. The presence of the patient with BLT is important for ascertaining the mechanism of the development of RSLT. Two umbilical veins are present initially during the embryonic stage. In general, the right-sided vein disappears, and the atrophic left-sided vein remains connected to the left portal vein originating from the vitelline vein. Several papers on the mechanism of the development of RSLT have been published. Some authors have mentioned that a residue of the right umbilical vein and the disappearance of the left umbilical vein are the causes of RSLT. On the other hand, some authors have asserted that RSLT is the result of atrophy of the medial liver area. The presence of BLT in patients indicates that the mechanism of the development of RSLT is characterized by a residue of the right umbilical vein and the disappearance of the left umbilical vein. CONCLUSIONS: The mechanism and origin of RSLT can be understood through cases of BLT, and surgeons must pay attention to anomalies of the portal and hepatic veins in patients with abnormal ligamentum teres.