ABSTRACT
Hypereosinophilic syndromes are characterized by very high levels of eosinophils in peripheral blood and a dysfunction of several organs as a consequence of their massive infiltration by eosinophilic cells. Cardiac alterations are traditionally known as fibroplastic endomyocarditis (Loeffler's Syndrome). We present the case of a female patient admitted in another center for the study of an accidentally discovered eosinophilia and referred to us because of her progressive hemodynamic deterioration followed by a poor clinical evolution. The anatomopathologic findings showed the classical injuries of this Syndrome; specially at cardiac level, where it is important to highlight the occupation of all the right ventricule's cavity by a clog. These injuries justified the origin of the stormy clinical presentation.