Congenital interruption of the inferior vena cava.

In the usual form of interruption of the inferior vena cava (IVC), the post-renal IVC continues as the azygos and hemiazygos vein. We report a patient with complete interruption of the IVC in whom no direct continuity existed between the IVC and the azygos system. Connection between these two systems was via the vertebral plexus and ascending lumbar veins. Associated venous malformations included bilateral azygos veins and anomalous connection of pulmonary and hepatic veins.