Superficial and Deep Vein Thrombosis Associated With Congenital Absence of the Infrahepatic Inferior Vena Cava in a Young Male Patient

Background Congenital absence of the inferior vena cava (AIVC) is a rare vascular anomaly that may be associated with deep vein thrombosis (DVT). It is underreported and may be present in up to 5% of young patients with DVT. We report a unique case of simultaneous thrombosis of both superficial and deep veins in a patient with AIVC. Methods and Results A 20-year-old man presented with a 2-week history of a swollen, painful, left lower limb. On examination, the left leg and thigh were found to be swollen and varicosities were present along the lower abdominal wall. Ultrasound showed extensive superficial and deep venous thrombosis of the entire left lower limb. Computed tomography venogram revealed an infrahepatic AIVC with lower limb drainage through enlarged intrathoracic continuations of the azygous and hemiazygous veins. The patient was put on oral anticoagulant therapy and was well at 6-month follow-up. Conclusion The hypothesis for DVT in patients with AIVC is that venous drainage of the lower limbs is inadequate, leading to venous stasis and thrombosis. All young patients presenting with idiopathic DVT should be investigated for inferior vena cava anomalies with computed tomography if ultrasound does not visualize the inferior vena cava.