---

Penetrating atheromatous ulcer is the condition in which ulceration of an aortic atherosclerotic lesion penetrates the internal elastic lamina into the media. Differentiation of penetrating atheromatous ulcer from other causes of acute aortic syndrome such as intramural haematoma and aortic dissection is difficult. The main symptom is a severe, acute chest pain radiating to the inter-scapular area, similar to classical acute aortic dissection of the thoracic aorta. In present article a case of a 52 years old woman with long- standing retrosternal chest pain and with penetrating atherosclerotic aortic ulcer in descending aorta was reported. Unlike the predominant picture of this disease,associated intramural hematoma was not seen.