Azygos vein aneurysm mimicking paratracheal mass: dynamic magnetic resonance imaging findings.

Aneurysms of the azygos vein are rare and can sometimes mimic a paratracheal or posterior mediastinal mass. It is important to confirm the diagnosis with radiologic tools before performing invasive procedures, which carry the risk of hemorrhage. Here, we present a case in a 79-year-old asymptomatic patient of an increasing azygos vein aneurysm that mimicked a growing paratracheal mass. Review of images obtained using various modalities, including dynamic magnetic resonance image (MRI), revealed that the image findings were suggestive of azygos vein aneurysm. Using this method, an exact diagnosis can be reached without resorting to invasive procedures.