[Dilatation of the azygos vein: an unusual cause of pulmonary mass].

Infrahepatic interruption of the inferior cava vein, is a rare congenital anomaly, usually associated with congenital heart and abdominal diseases. The systemic venous flow is accommodated by the dilated azygos. This dilated azygos arch accounts for the right paratracheal or mediastinal mass, and may be misinterpreted as a neoplasm. We report a case with this congenital vascular anomaly, associated with another of tracheobronchial tree.