Survival after acute necrotizing eosinophilic myocarditis complicating a massive left ventricular mural thrombus: a case report.

An 81-year-old man was referred to our hospital with exertional dyspnea following cold-like symptoms. Electrocardiography revealed ST elevation and positive T wave in leads I, II, aVL, aVF, and V2-V6. The diagnosis was acute myocarditis complicating heart failure. He was conservatively managed. On hospital day 8, brain infarction developed and echocardiography disclosed massive mural thrombus in the left ventricle. Left ventriculotomy was performed on hospital day 21 and histological examination showed inflammatory cell infiltration mainly composed of eosinophils and monocytes, degeneration of myocytes with replacement fibrosis, and fresh fibrin thrombus overlaying the endocardium. These findings were compatible with a diagnosis of acute necrotizing eosinophilic myocarditis(ANEM). He recovered uneventfully without specific therapy. This case suggests that a subtype of ANEM might be self-limiting.