Inferior Vena Cava Agenesis, a Forgotten Etiology of Deep Vein Thrombosis in Young Patients: A Case Report

Agenesis of the inferior vena cava (IVC) is a rare congenital anomaly that is associated with the development of extensive collateral circulation with the aim of compensating for the inadequate return of blood to the right ventricle. This collateral circulation predisposes to the emergence of venous hypertension with stasis and thrombus formation. Most cases are asymptomatic and are diagnosed incidentally. We report the case of a 28-year-old man who presented with bilateral deep vein thrombosis (DVT) as the first manifestation of agenesis of the IVC. We decided to maintain anticoagulation for an indefinite period of time after a multidisciplinary discussion. IVC agenesis should be considered a cause of DVT in young men, with bilateral and proximal thrombosis and without other risk factors. The rarity of the condition makes its therapeutic approach complex.