The authors describe a case of sudden cardiac death caused by the simultaneous multivessel rupture of unstable atherosclerotic plaques, triggered by a transmural inflammatory process (coronaritis). Male subject, 44 years old, apparently in good health until 1 hour before death, when he complained of worsening dyspnea. At autopsy, it was found that the heart weighed 486 g. Evaluation of the coronary arteries revealed the presence of atherosclerotic plaques resulting in a lumen critical stenosis of the left anterior descending artery (LAD), right coronary artery (RCA) and left circumflex artery, and acute occlusive thrombosis of the LAD and RCA. Transverse sections of the ventricular mass highlighted the presence of eccentric hypertrophy of the left ventricle associated with myocardiosclerosis of the posterior interventricular septum and of the posterior wall of the left ventricle. Histology revealed the presence of a coagulative myocytolysis ascribable to the free walls of the left ventricle, and a focus of lymphocytic-active myocarditis. All coronary arteries were sites of intima fibroatheromatous plaques complicated by rupture and thrombosis within the RCA and LAD and by a transmural infiltrate consisting of macrophages and T-lymphocytes associated with consensual medionecrosis and perineuritis. In conclusion, the present case report confirms the hypothesis that inflammation plays a key role in the onset of acute coronary syndromes as it promotes the formation of an unstable plaque as well as its rupture.