Aneurysm of the inferior vena cava: case report and review of the literature.

Aneurysms of the inferior vena cava (IVC) include a diverse group of anomalies with distinct anatomic and clinical characteristics. We report a diverticular aneurysm of the suprarenal IVC in a 45-year-old man who presented with extensive IVC and unilateral lower extremity thrombosis. A CT scan revealed an 8 cm smooth-walled mass containing thrombus to the right of the IVC and behind the second portion of the duodenum. At laparotomy a connection between the mass and the suprarenal IVC was established. Biopsy of the wall of the mass revealed vascular smooth muscle, thus establishing the diagnosis of a diverticular IVC aneurysm. MR angiography further disclosed interruption of the infrahepatic vena cava and return of renal vein flow via the azygous and hemiazygous veins. Twelve additional cases of IVC aneurysm are reviewed. A proposed classification of these aneurysms into four types consistent with their anatomic and embryologic characteristics is presented.