Three main portal veins: A very rare case of portal vein anomaly.

Portal vein (PV) anomalies are rare during embryonic development, with very few cases of duplicated PVs reported. This case reveals a new PV trunk anomaly, where computed tomography venography imaging shows three portal veins. The superior mesenteric vein and inferior mesenteric vein join to form a trunk that divides into two branches: One entering the liver (PV1) and the other ascending to join the splenic vein. The splenic vein then divides into two branches in the neck of the pancreas (PV2 and PV3), both entering the liver. The three PVs vary in thickness and all enter the liver through the first hepatic portal. Understanding the normal structure and anatomy of the PV is important for successful surgical planning. This case involves three main trunks of the PV, which is an extremely rare type of PV duplication anomaly. Reporting this case aims to enhance the awareness and understanding of PV duplication anomalies among clinicians and radiologists.