Spontaneous rupture of thoracic aorta without aneurysm formation is extremely rare. A case of spontaneous rupture through an atheromatous plaque in an 82-year-old woman is reported. She presented with atypical chest pain, and chest radiography revealed no evidence of aneurysm. She died suddenly in the hospital within 24 h after admission. At autopsy, there was an intimal tear and rupture of the descending aorta through an atheromatous plaque, resulting in massive hemothorax. The previous reported cases of spontaneous aortic rupture were reviewed. The pathology of spontaneous aortic rupture are discussed with emphasis on the dating of the rupture, which may have significant medicolegal importance.