Introduction: The idiopathic hypereosinophilic syndrome is a rare haematologic disorder difficult to treat. We report the efficacy of imatinib mesylate in this pathology.
Exegesis: An idiopathic hypereosinophilic syndrome associated with a cutaneous mastocytosis was diagnosed in a 32-year-old man presenting with pulmonary, neurological and haematological manifestations. After failure of interferon alpha and hydroxy-urea therapy, a durable and complete clinical and biological remission was induced by imatinib mesylate within 3 weeks.
Conclusion: Imatinib mesylate, an inhibitor of tyrosine kinases appears to be a very safe and effective treatment for this type of hypereosinophilia. The mechanism of response to this molecule, well known in Philadelphia positive chronic myeloid leukemia, is not yet clarified in the idiopathic hypereosinophilic syndrome (other oncogenes than c-kit or PDGF could be concerned). The association with cutaneous mastocytosis has not been reported yet.