A case of spontaneous innominate artery perforation with pericardial tamponade.

We describe a case of a spontaneously occurring innominate artery perforation which, rather than resulting in immediate death, developed a subacute course with findings suggestive of an expanding mediastinal mass. The cause of the spontaneous perforation appears to have been a combination of atherosclerosis, infection, and infiltration of the underlying structures with malignancy. This is a unique case of subacute spontaneous perforation of a great vessel.