Subclavian vein obstruction with collateral flow through the umbilical and hepatic veins.

Upper venous return to the heart can be obstructed by any number of pathologies and often leads to formation of collateral pathways around the obstruction. This case report describes a thrombotic obstruction of the left subclavian and brachiocephalic veins and a collateral pathway involving recanalization of the umbilical vein. Even more rare and unique is the anastomosis of the recanalized umbilical vein to the middle and left hepatic vein rather than the portal vein. The anatomy of the expected collateral pathways and the anastomotic vascular anomaly is described in detail, including a discussion of the embryological development of the system.