The Deep venous thrombosis (DVT) in the iliofemoral region may be more common than previously thought. 1 Acute iliofemoral DVT is associated with the highest risk of post-thrombotic morbidity. To prevent post-thrombotic syndrome, strategies for early removal of thrombi have been recommended and widely accepted in the United States, regardless of the patient’s age. 2,3 However, pre-existing venous disease, such as absent inferior vena cava (IVC) syndrome, can make this treatment more difficult.

A congenital anomaly of the IVC and its tributaries is a rare vascular malformation. Abernethy was the first to describe a congenital mesocaval shunt and azygos continuation of the IVC in a 10-month-old infant with dextrocardia in 1793. 4 Between weeks 6 and 8, the IVC and adjacent urogenital drainage system undergo complex embryogenesis.