[Hypereosinophilic syndrome with Löffler's endomyocarditis: report of an autopsy case].

Hypereosinophilic syndrome (HES) with Löffler's endomyocarditis is a rare disease with poor prognosis. Clinically, it mainly affects young adults, characterized by prolonged idiopathic blood eosinophilia, cardiopulmonary symptoms and hepatosplenomegaly. Pathological features consist of ventricular mural thrombi, marked fibrotic thickening of endocardium with scarring of myocardium, and multiorgan eosinophilic infiltration. We report a 2-year-old girl with idiopathic HES associated with Löffler's endomyocarditis. The girl was noted to have constitutional symptoms, cardiomegaly, and hepatosplenomegaly. Her total eosinophil count reached 150,000/microliters. She had no history of allergic diseases. The microbiological studies were negative. Echocardiography suggested thickened endocardium, mitral stenosis and regurgitation. In spite of intensive medical management, the girl died of refractory congestive heart failure. Autopsy revealed thick fresh mural thrombi involving the biventricular inflow tracts, inflammation and fibrosis of the endomyocardium, systemic thromboembolism and multiorgan eosinophilic infiltration. The pathology and pathogenesis of the disease are discussed and the literature is reviewed.