Inferior Vena Cava Agenesis with Paravertebral Muscle Collateralisation

Developmental anomalies of the inferior vena cava (IVC) have an estimated prevalence of 0.5%, and may be the common aetiology in young patients presenting with bilateral lower limb iliofemoral thrombosis. We report a case of spontaneous bilateral iliofemoral deep venous thrombosis secondary to infrahepatic IVC agenesis. The patient had associated thrombosis of the azygous and hemiazygous venous system and collateralisation via the venous plexus of the paravertebral muscles. To our knowledge, this is the first such case reported of IVC agenesis dependent upon collateral return via the paravertebral muscles.