[Loeffler's endocarditis--a case report].

Loeffler's endocarditis is an acute form of primary restrictive cardiomyopathy. We report the case of a young woman with pleuritic chest pain associated with fever and hypereosinophilia. She was hospitalized with suspected acute myopericarditis and was treated with aspirin, leading to clinical improvement. Ten days after discharge, she was rehospitalized due to recurrence of chest pain. The echocardiogram showed what appeared to be a mass filling the apex of the right ventricle (RV). She was referred for magnetic resonance imaging, which revealed marked myocardial thickening in the apex of the RV. The patient underwent an endomyocardial biopsy, resulting in a diagnosis of eosinophilic endocarditis. After treatment with prednisolone, all symptoms and the eosinophilia disappeared, and there was complete remission of the RV abnormalities. After three years of follow-up, the patient remains asymptomatic. This case shows that, even without an etiologic diagnosis of eosinophilia, the prognosis for Loeffler's endocarditis can be favorable if treatment is initiated early.