A 34 year-old male patient suffered an acute anterior wall infarction at age 32. Myocardial ischemia was demonstrated later by stress testing and thallium myocardial scintigraphy. Coronary arteriography revealed a proximal 90 per cent obstruction of the left anterior descending artery. The patient was submitted to percutaneous transluminal coronary angioplasty. The procedure was unsuccessful as the catheter could not progress through the obstruction. On follow-up, there was less than ideal adherence to medical treatment and the patient complained of occasional atypical non-effort related chest pain. Two years later the patient suffered a large fatal myocardial infarction. Necropsy disclosed that the cause of myocardial infarction was severe coronary arteritis of left circumflex artery with giant cell granulomas