A 66-year old man was admitted to the hospital with chest and back pain and wide chest wall ecchymosis. His medical history revealed no chest trauma or resuscitation, but coronary angiography had been performed 20 days previously. Subacute type A aortic dissection was diagnosed. The likely cause of an ecchymosis located in this way, correlated with vasculature of thoracic wall, was thought to be progression of the dissection through the arterial branches feeding the chest wall. Perioperative observation confirmed the diagnosis and a hemiarch replacement was performed with a good outcome.