A 42-year-old man presented to his primary care provider office with symptoms of upper respiratory tract infection and episodic dull chest pain for 3 days. Chest pain was located over anterior precordium and retrosternum, increased in intensity with inspiration and body movement. On examination his vitals were stable except for pulse of 115 beats per minute. Physical examination was otherwise unremarkable. Electrocardiogram performed in the office revealed diffuse ST-segment elevation of 1-2 mm and diffuse PR-segment depression. Portable chest x-ray was unremarkable without mediastinal widening. He was diagnosed with acute pericarditis. However due to suspicion of acute coronary syndrome he was referred to emergency room for possible admission to coronary care unit for observation. In the emergency room on re-examination he is alert but uncomfortable. Blood pressure was 140/82 mm Hg in all extremities; pulse was 103 beats per minute and regular. His chest is clear and careful cardiac examination revealed a 2/6 early diastolic murmur in aortic region. First set of cardiac enzymes was negative. Repeat ECG was similar to previous one. Incidentally ordered CT scan of chest was reported as Stanford Type-A thoracic dissection. He was immediately started on IV labetolol drip and admitted to intensive care unit. Emergent cardiothoracic surgery consultation was placed. Patient successfully underwent aortic repair without complication. Thoracic aortic dissection is a life-threatening condition associated with high rates of morbidity and mortality. It is the most common acute aortic condition requiring emergent surgical therapy. The incidence of aortic dissection has been estimated at from 5 to 30 per 1 million people per year. Dissection is a dynamic process that can occur anywhere within the aorta and is characterized by separation of the layers within the aortic wall.Thoracic aortic dissection has long been known to mimic multitude of clinical conditions. It is usually associated with severe chest pain and or back pain and is the most frequent fatal condition in the spectrum of chest pain syndromes. We present a young patient with cystic medial necrosis who presented with atypical clinical symptoms and ascending thoracic aortic dissection was diagnosed by CT imaging. Patients with cystic medial necrosis and aortic dissection may not present with a classic acute chest pain syndrome. Due to variable clinical presentation, dissection of thoracic aorta can be a diagnostic challenge for physicians. Therefore a high clinical index of suspicion is necessary.