A Case of Myocardial Infarction With Nonobstructive Coronary Arteries due to the Compressive Effects of a Type B Thymoma With Internal Hemorrhage

Our case was a 45-year-old woman who presented with a chief complaint of intermittent typical chest pain. In electrocardiography, ST-elevation in the lateral leads was observed. Echocardiography showed mild left ventricular systolic dysfunction with hypokinesia in the anteroapical segment. Coronary angiography was normal, and chest computed tomography showed a large mediastinal mass without any compression on the coronary arteries. Cardiac magnetic resonance imaging demonstrated a nonhomogeneous encapsulated mass close to the right ventricle and adjacent to the ascending aorta, the pulmonary artery trunk, and the superior vena cava, with compression effects on the coronary artery. There was transmural gadolinium enhancement in the mid-to-apical anterior and inferior walls with akinesia in these segments, in favor of myocardial infarction with nonobstructive coronary arteries. The patient underwent surgical mass resection, and the pathological investigation confirmed the diagnosis of a type B1 thymoma. (Iranian Heart Journal 2022; 23(1): 214-219)