Ultrasound Detection of Absent Inferior Vena Cava

The congenital absence of the inferior vena cava (AIVC) is a rare condition affecting any portion of the infrahepatic IVC. Most confirmed patients are male, with unilateral or bilateral deep vein thrombosis (DVT) involving the iliac and femoral veins. AIVC is typically diagnosed by computed tomography (CT) or magnetic resonance imaging after an abnormal lower extremity venous ultrasound study. The following case report involves a 30-year-old man who developed a unilateral iliofemoral DVT without known risk factors. CT scan confirmed the presence of DVT but failed to identify AIVC. Repeat ultrasound imaging identified the absence of the IVC and common iliac veins, which was confirmed by venogram.