Aneurysmal Coronary Artery Disease (ACAD) can occur as localized dilations of a segment of one or more coronary arteries or diffuse ectasia-type dilatations of one or more coronaries. Atherosclerosis remains the most common cause of these aneurysms, with Kawasaki Disease being implicated in the Asian population. We present a case of a 62-year-old Asian woman who dies suddenly with no prior symptoms. and underwent an autopsy. Her heart showed diffuse aneurysmal dilatations of the epicardial coronary arteries, with a giant saccular aneurysm of the left main coronary artery. Histopathology revealed medial degeneration of the aneurysmal wall with no evidence of atheroma or vasculitis. Following a review of the pathological causes of coronary aneurysms, it is likely that the cause of such diffuse dilatations of the coronaries could be previous vasculitis such as Kawasaki disease.