Introduction - The preferred treatment for non-thrombosed acute aortic dissection of the ascending aorta is surgical intervention [1-3]. For thrombosed type dissection of the ascending aorta best treatment remains debatable. Studies from Asia have recently shown medical treatment to be a reasonable alternative for this specific subgroup [4-8]. Absence of an intimal tear is thought to be important for a safe conservative treatment strategy. In this case report we present a patient with acute aortic dissection Stanford type A with an entry tear and thrombosis of the false lumen of the ascending aorta who was managed with conservative treatment. Methods - A 69-year-old white female was referred to our center with acute onset of upper abdominal and back pain. She was hemodynamically stable with no signs of shock. The patient had multiple peripheral vascular bypasses in the year before admission and an aortic tube graft seven years earlier for an infrarenal inflammatory aneurysm. Computer tomography angiography (CTA) showed a circular intramural hematoma (maximum diameter 5mm) from the aortic root to the proximal descending aorta where a penetrating atherosclerotic ulceration was visible 7 cm from the origin of the left subclavian artery with asymmetric intramural hematoma blood pools in the descending aorta. There was no sign of pleural effusion, pericardial effusion, or organ ischemia. The echocardiogram showed good left ventricular function without aortic valve regurgitation and a moderately dilated ascending aorta to 4.2 cm with a thickened wall. The combination of an entry tear distal from the left subclavian artery and intramural hematoma of the ascending aorta provided a treatment dilemma, since it is difficult to treat both lesions using a single approach. The upper abdominal and back pain had subsided at presentation to our center and the patient was clinically stable; therefore we opted for a conservative approach with close observation. The patient was admitted to the intensive care unit and antihypertensive therapy aimed at maximum systolic pressure of 100 mmHg was initiated, with re-evaluation multiple times every shift. Follow up CTAs were performed on days 2, 3, 10, 14, 21 and 28. During her hospital stay, the patient occasionally experienced mild pain, which responded well to medication. With systolic blood pressures of 130mmHg, on day 10 the intramural hematoma (IMH) in the ascending aorta had grown to 10mm. With tighter blood pressure control the IMH decreased and no further progression in hematoma thickness or aortic diameter was observed on subsequent CTA scans. Progression of the intramural blood pools in the descending aorta was treated conservatively. Follow up 4 weeks after discharge (day 59) showed remodeling of the ascending aorta with persistent blood pools in the descending aorta and only minimal further dilatation. Results - CT-angiogram on day 10 (left) vs day 59 (right) showing resolution of the intramural hematoma and remodeling of the ascending aorta. Conclusion - Dissection involving the ascending aorta is a life-threatening condition for which operative treatment is recommended in most cases. In thrombosed dissection, conservative therapy with close observation and willingness to convert to immediate surgery may be considered. This approach can lead to complete remodeling of the ascending aorta.