Complicated Azygos Vein Aneurysm in an Infant Presenting with Acute Pulmonary Thromboembolism.

Azygos vein aneurysm is a rare cause of mediastinal mass. Most cases present as an incidental finding on imaging modalities, but in few cases the thrombosis in the aneurysm leads to pulmonary thromboembolism, which may require surgical resection. We present a case where, for the first time, a case of a complicated azygos vein aneurysm was diagnosed in infancy, which required surgical resection.