Bilateral umbilical portions of the portal vein with paired ligamenta teres converging into a single falciform ligament: an anatomic variation with surgical implications.

purposeAnatomic variations of the portal venous system are clinically important, yet bilateral umbilical portions (UPs) of the portal vein are extremely rare, particularly when accompanied by paired ligamenta teres within a single falciform ligament. We describe this exceptional configuration and discuss its clinical implications.

methodsAn 82-year-old man underwent preoperative evaluation for pancreaticoduodenectomy. Contrast-enhanced multidetector CT and three-dimensional reconstruction were performed to assess tumor resectability and hepatobiliary anatomy. Intraoperative inspection of the falciform and round ligaments was undertaken during surgery.

resultsImaging demonstrated two distinct umbilical portions arising from the main portal vein and extending toward the right and left umbilical fissures. Cord-like structures compatible with paired ligamenta teres were visualized from the blind ends of each UP. Intraoperatively, both ligamenta teres were confirmed and were found to converge cranially into a single falciform ligament on the diaphragmatic surface of the liver. No biliary or arterial anomalies were identified. Pancreaticoduodenectomy was completed uneventfully, and the patient remained recurrence-free for five years.

conclusionThis rare arrangement may reflect symmetrical persistence of vitelline venous channels during portal venous morphogenesis. Awareness of this variation is important to avoid radiologic misinterpretation and to prevent misidentification of hepatic landmarks during hepatobiliary surgery.