Interruption of the inferior vena cava IVC) with azygos continuation is an uncommon vascular anomaly that results from aberrant development during embryogenesis. We report a rare case of this anomaly, presenting with massive pulmonary embolism. Subsequent evaluation with abdominal CT scan revealed the congenital absence of retrohepatic IVC. The patient was successfully treated with anticoagulation. When deep venous thrombosis (DVT) develops in patients with no apparent risk factors, the presence of congenital IVC anomalies should be considered.