Spontaneous nontraumatic rupture of the thoracic aorta is a very rare, life
-threatening condition for which emergency diagnostic and therapeutic measu
res are indicated. The patient reported herein suffered a spontaneous ruptu
re of the thoracic descending aorta through an atheromatous plaque without
aneurysmal formation. When acute intrapericardial, mediastinal, or intraple
ural bleeding develops without any evidence of aortic aneurysm or dissectio
n, the possibility of spontaneous rupture of the thoracic aorta should be c
onsidered in the differential diagnosis, and appropriate emergency surgery
may be life-saving.