Deep venous thrombosis complicating a congenital absence of the inferior vena cava

An unusual course of the right renal artery associated with an anomalous inferior vena cava

In a 55-year-old male cadaver, the inferior vena cava bifurcated at a level midway between the hilus and inferior pole of the right kidney. The narrower branch, on the right side, drained the right renal and hepatic veins, ascended as the normal inferior vena cava, passed through the caval opening of the diaphragm and drained into the right atrium. The wider branch on the left side drained the left renal vein and penetrated the right crus of the diaphragm as the azygos vein. This vein ascended in the posterior mediastinum and drained into the superior vena cava. The hemiazygos and accessory hemiazygos veins were absent. In addition to these anomalies, the right renal artery entered the hilus after coursing through the above-mentioned two branches at the bifurcation. No congenital anomalies of the heart or abdominal viscera and main arteries were seen.

Absence of the inferior vena cava causing repeated deep venous thrombosis in an adult--a case report

Agenesis of the inferior vena cava is an uncommon congenital vascular malformation. Although theoretically it may favor venous stasis, it is not normally associated with venous thrombosis. The authors found only three reports of the coexistence of both entities, and only one of these rules out the existence of associated hypercoagulability. They report the case of a patient with a history of repeated venous thrombosis. Magnetic resonance angiography and venography demonstrated complete agenesis of the inferior vena cava and persistence of a cardinal venous system with azygos and hemiazygos continuation, associated with right renal hypoplasia. Studies ruled out hypercoagulability syndrome, either primary or secondary to an occult neoplasm. The authors conclude that venous malformations, although rare, may cause thromboembolic disease, especially in young patients, and that magnetic resonance angiography is a useful diagnostic alternative to conventional phlebography.