We report the case of a young male with an inferior myocardial infarction who was treated with fibrinolytic agents and displayed a good evolution. The only cardiovascular risk factor that this patient had was an idiopathic thrombocytosis with abnormal platelet hyperreactivity tests. The angiogram showed an eccentric lesion of 60% in the left main coronary artery. A week later, after treatment based on anticoagulants and antithrombotic agents the angiogram was normal, and the lesion had dissappeared. The association between these conditions is discussed and the therapeutic approach is also discussed. A review of the literature is conducted.