Penetrating aortic ulcers (PAU) result from progressive erosion of atheromatose plaques perforating the internal elastic lamina. PAU is considered both a predisposing condition and differential diagnosis of classic aortic dissection; 93 cases of PAU are documented in the world literature, 60% of which are male over 60 years old. Systemic hypertension was prevalent in 85%, history of smoking in 72%, hyperlipoproteinemia in 35%, and diabetes mellitus in 31%. In 61%, PAU was associated with coronary artery disease, in 53% with abdominal or thoracic aortic aneurysm, in 31% with chronic renal insufficiency, in 17% with peripheral artery disease, and in 12% with a history of cerebrovascular accidents. In 73%, PAU was associated with formation of medial hematoma and in 16% with a thick, calcified intimal flap of less than 10 cm extent. Angiography, computed tomography, magnetic resonance imaging and transesophageal echocardiography were used in 66, 64, 23 and 14%, respectively, for diagnosing PAU; sensitivities for demonstrating PAU were 83, 65, 86 and 61%, respectively. Chest or back pain was found in 76% and an acute onset of symptoms in 68%. Signs of mediastinal widening were found in 59%, neurologic signs comprising hoarseness, syncope or coma in 8%, pulse differentials caused by embolism in 4%, aortic regurgitation in 7%, and mediastinal hematoma, pleural- or pericardial effusion in 42, 27 and 10%, respectively. PAU of the ascending aorta or aortic arch (type A) leads to dissection and rupture in 57%, compared to 12% and 5%, respectively, in the descending aorta (type B); 57% of medically managed type A PAU patients died within 30 d of hospital admission compared to only 14% of type B PAU with 20 cases of uncomplicated long-term outcome without surgery. Thus, similar to the Stanford classification for aortic dissection, type A PAU should primarily be considered for surgical management, whereas type B PAU without signs of instability may be managed medically.