Casual recognition of an azygous continuation of the inferior vena cava ina patient with lung cancer

Anomalous continuation of the inferior vena cava with an azygous vein is a rare vacular anomaly. The enlarged venous system may simulate adenopathies or mediastinal and retroperitoneal masses on the radiographs, We describe t he case of a patient with lung cancer - a pathological condition which may cause adenopathies at these sites - and a dilated azygous-hemiazygous syste m resulting from failure of formation of the hepatic segment of the inferio r vena cava.