IVC agenesis: a rare cause of deep vein thrombosis.

We present the case of a healthy, young Caucasian female who presented to an outside hospital with phlegmasia cerulea dolens of both lower extremities. Computed tomography angiography revealed inferior vena cava (IVC) occlusion. She was initiated on heparin infusion and transferred to University of Virginia Medical Center. Our evaluation revealed aplasia of the IVC from the infrahepatic segment to the confluence of the common iliac veins and acute bilateral iliac vein thromboses. An extensive network of collateral veins was noted. These findings were consistent with IVC agenesis. She was not pregnant or using contraception. Primary thrombophilia workup was negative. She underwent bilateral iliac vein thrombolysis and was started on anticoagulation. While IVC agenesis is rare, it carries risk for development of thrombotic sequelae and bears consideration when evaluating young patients with unexplained deep vein thrombosis, especially if extensive and bilateral.