[Durable efficacity and remission after treatment with imatinib mesylate for FIP1L1-PDGFRA transcript negative associated eosinophilic cardiomyopathy].

Introduction: The cardiac involvement in hypereosinophilia remains a major cause of morbidity and mortality. Recent advances have identified new molecular mechanisms responsible for the expansion of the eosinophilic lineage, allowing a better classification of the different forms of Hypereosinophilic syndrome (HES) and especially targeted therapy. Since the discovery of the involvement of deregulated tyrosine kinases in the pathophysiology of these diseases, and particularly the identification of the fusion gene FIP1L1-PDGFRA, new molecules inhibiting specifically this signaling pathway (imatinib) were individualized, leading to dramatic therapeutic benefits in proliferative forms of HES considered before that of very poor prognosis.

Case Report: We report here the dramatic effectiveness of imatinib used as second line therapy for dilated cardiomyopathy revealing a hypereosinophilic syndrome in a patient in whom the search for FIP1-L1-PDGFRA fusion gene was negative.

Conclusion: If hypereosinophilia has varied clinical and morphological outcome, its clinical consequences, particularly on heart function, are sometimes dreadful, and are not correlated either with blood eosinophil levels or with a specific etiology. We report here a case of HES lacking the FIP1-L1-PDGFRA fusion gene showing that despite the absence of this molecular defect, imatinib mesylate may have therapeutic interest in those cases of HES resistant to first line therapies.