The authors report two new cases of spontaneous dissection of the coronary arteries in women under 50 years of age without any predisposing factors and responsible for sudden death. One patient had dissection of the left anterior descending artery and the other had dissection of the left anterior descending and right coronary arteries. Special histological stains allow demonstration of abnormalities of the elastic tissue of the media in both cases. In the first case, a plaque of atheroma was present opposite the site of dissection but did not seem to be causal. In the second case, severe periadventitial cellular, infiltration of unknown origin was observed. This pathology of the young woman, often occurring in the postpartum period, is as rare as it is unpredictable.