Absent left and right superior vena cava and azygos continuation of inferior vena cava: a rare anomaly of systemic venous return.

We report a case of a complicated vascular access secondary to systemic venous defects which have not been previously reported. Further evaluation revealed congenital absence of superior vena cava with two brachiocephalic veins draining separately. He also had absence of the hepatic segment of the inferior vena cava with azygos continuation. The patient did not have congenital anomalies of the remaining thoracoabdominal vasculature and viscera.