Multiple portal veins in the hepatoduodenal ligament: Evidence of "duodenal reverse rotation" hypothesis?

Duplication of the portal vein is a rare variation, and reports of this condition are quite limited. The present report describes a woman of advanced age who was incidentally diagnosed with duplicated portal veins. The portal vein from the splenic vein distributed to the left lobe of the liver, and that from the superior mesenteric vein ran between the pancreas and duodenum to distribute to the right lobe. The former portal vein connected with the round ligament, and its presumptive origin was the left vitelline vein. The latter was presumably from the right vitelline vein. Between the 2 portal veins, 2 anastomotic veins were identified; one anastomosis was posterior to the pancreatic head, and the other was intrahepatic. The common bile duct was located posterolateral to the portal veins. The relationships of these veins to the round ligament and common bile duct support the reverse rotation hypothesis of the duodenum in the development of portal vein variations.