Successful Treatment For Chronic Eosinophilic Leukemia (CEL) With Imatinib Mesylate

Abstract

We report a case of a patient with Chronic Eosinophilic Leukemia (CEL) with mutation in alfa PDGFR gene exhibiting a satisfactory response to treatment with imatinib mesylate. A 25-year-old man presented in a hematology service with a persistent cough and hemogram alterations. His blood count showed a hemoglobin level of 12.5 g/dL and a white blood cell count of 94,030/mm3, eosinophils were 68% of all cells. Bone marrow aspiration and biopsy showed hypercellularity with marked eosinophilia (77%) and erythroid differentiation series was hypocellular with normoblast maturation. The immunohistochemically of the bone biopsy was positive for myeloperoxidase and negative for CD34/CD99, consistent with CEL. Fluorescence in situ hybridization (FISH) for the beta-fraction of platelet-derived growth factor (PDGFRβ) and Philadelphia chromosome (Ph 1) were negative and the alfa PDGFR (Platelet-Derived Growth Factor) was positive and showed heterozygosis in c.2531T>C on 18 Exon and homozygous in C.2562+1G>A at the region of the splicing site at the 18 intron. Treatment was initiated and maintained by administering 400mg/day imatinib mesylate. Laboratory findings returned to normal ranges, with clinical improvement and a hematological response observed after the second month of therapy. Currently, the patient’s blood count shows the white blood cell count (5,400 total leukocytes), eosinophils (8.6/mm3), hemoglobin (15.5 g/dl), hematocrit (45.4%) and platelets (298,000/mm3) within normal ranges. The mutation search was negative in in peripheral blood one year after the initial treatment. Our work corroborates other studies on the efficacy of imatinib mesylate in the treatment of patients with CSF PDGFR alpha positive. We emphasize the importance of molecular studies, considering its relevance for the correct staging of the disease. Since CEL is a rare disease, it is important to define its etiology and anticipate its treatment, thus minimizing the damage induced by the disease.