Absence of the inferior vena cava (IVC) is an uncommon congenital abnormality. Symptoms of lower extremity venous insufficiency resulting from this anatomic abnormality have been reported only once in the English literature, and no experience with surgical treatment of this condition has been published. We report the case of an otherwise healthy 41-year-old man with an 18-month history of severe venous insufficiency involving the right leg manifested by extensive ulceration that did not respond to aggressive conservative treatment. Duplex findings were not suggestive of venous obstruction or reflux, but venography documented no filling of the common iliac vein or inferior vena cava, and outflow was via collaterals to the azygous and hemiazygous systems. Computed tomography demonstrated complete absence of the inferior vena cava with azygous continuation. A prosthetic bypass from the external iliac to the intrathoracic azygous vein was performed with complete symptomatic relief after a 30-month follow-up period. Venous bypass surgery may play a role in treatment of this rare cause of venous insufficiency.
