Dual inferior vena cava: two inferior vena cava filters.

The formation of the venous drainage system of the human body is a complex process involving structures forming and regressing in a predefined order. Interruption of any one of these steps results in the formation of a congenital anomaly. Knowledge of these anomalies can prevent us from potential serious and sometimes fatal complications. Variations from the normal anatomy of the inferior vena cava (IVC) occur in 3% of the population. The complex embryology of the IVC stems from three pairs of fetal veins: (1) posterior cardinal veins, (2) subcardinal veins, and (3) supracardinal veins. The cardinal veins constitute the main venous drainage system of the embryo. Although venous anomalies are rare, their knowledge is crucial in diagnosis and treatment. These variations should not be mistaken for pathologic finding, but should be viewed as normal findings of abnormal embryogenesis. We present a case here identifying a dual IVC, subsequently leading us to place two IVC filters.