Leucemia eosinofílica crónica con respuesta hematológica sostenida tras tratamiento con bajas dosis de Imatinib

Resumen

Hypereosinophilic syndrome is defined as any sustained eosinophilia without secondary cause. It is classified into three categories: idiopathic hypereosinophilic syndrome, hypereosinophilia secondary to IL-5 overproduction by T cells clonality and chronic eosinophilic leukemia associated with chromosomal rearrangements.

We report a 58 year-old-man, previously healthy, consulting for two months of weight loss, asthenia and cephalea. His initial laboratory assessment showed leukocytosis 16100/mL with 65% eosinophils and absolute eosinophil count of 10465/mL. Both bone marrow biopsy and myelogram showed bone marrow infiltration by mature appearance eosinophils.

 Treatment was started with hydroxyurea, associated with prednisone without satisfactory decrease in the eosinophil count. The study by PCR showed the presence of the gene fusion product FIP1L1/PDGFRA. Imatinib therapy was initiated, resulting in a rapid and progressive absolute eosinophils count, with normalization at the second week of treatment. Although the incidence of myeloproliferative variant to cause hypereosinophilic syndrome is rare, the exquisit response to imatinib emphasizes the need to study the presence of the fusion product FIP1L1/PDGFRA in all patients with sustained eosinophilia with no other cause shown.