[Aneurysm of the superior vena cava, Apropos of 1 case].

Report of the case of a seventeen-year-old man in whom was discovered in the course of a systematic X-ray examination of the thorax a shadow of the right upper mediastinum. The variability of the pictures in relation with the upward or supine position, suggest the diagnosis of a vascular tumour, which was confirmed by angiocardiography. Towards the end of this examination there was a cardiac arrest with coma, which was suggestive of the probable diagnosis of thrombo-embolic accident, and the operation was undertaken under extracorporeal circulation.