Duplication of the inferior vena cava: anatomy, embryology and classification proposal.

A case of a duplicated inferior vena cava (IVC) along with other anatomical vessel variations in a 72-year-old male cadaver is presented. The anomalous vessels involved, besides the IVC, were the left testicular vein and artery, the left suprarenal artery and a superior accessory left renal artery. Based on the gross appearance of the preaortic anastomotic trunk between the left and right IVC as well as on the underlying embryological features, a classification is proposed: incomplete bilateral duplication of the IVC and complete bilateral duplication of the IVC. The latter can be further divided into three types: major, minor and asymmetric.