Hypereosinophilic Syndrome: a rare case of Loeffler's endocarditis documented in cardiac MRI.

Cardiac manifestation of Hypereosinophilic Syndrome usually presents as Loeffler's endocarditis; this case of unusual manifestation of Hypereosinophilic Syndrome, however, revealed restrictive left ventricular dysfunction and increased left ventricular wall mass. Both, an endocardiac eosinophilic mass and layers of intraventricular thrombus were demonstrated and followed by echocardiography and MRI under treatment. The current case demonstrates not only the diagnostic potential of magnetic resonance imaging (MRI) to visualize eosinophilic infiltrate and thrombus, but also morphologic changes with treatment by oral anticoagulation and immunosuppression. With 6 months of intense medical treatment cardiac MRI was instrumental to document both the endocardiac mass and improvement of left ventricular function.