[A case of idiopathic aneurysm of the inferior vena cava].

Congenital aneurysms of the inferior vena cava (IVC) are very rare, and to our knowledge, only 4 cases have been previously reported. We describe the fifth case of fusiform aneurysm and briefly review the literature. A 62-year-old woman was admitted to our hospital for investigation of a mass shadow on the right hemidiaphragm on a chest roentgenogram. CT, MRI, and DSA examinations revealed an aneurysmal dilatation of the IVC measuring 51x50x38 mm inferior to the right atrium, and the diagnosis of fusiform aneurysm of the IVC was made. The newer imaging techniques of CT, MRI, and DSA have facilitated the diagnosis of this abnormality.