Granular acute lymphoblastic leukemia with hypereosinophilic syndrome

A four-year-old boy presented with marked peripheral blood eosinophilia (absolute eosinophil count of 54 x 10(9)/1), features of hypereosinophilic syndrome, and acute lymphoblastic leukemia (ALL-L2), the latter characterized by the presence of granular blasts. Blasts were negative for myeloperoxidase, non-specific esterase, acid phosphatase, periodic-acid Schiff stain, and toluidine blue. They exhibited an early pre-B immunophenotype (TdT, CD19, CD10, CD20 and CD22 positive) and stained negative for T (CD7, CD2, CD5 and CD3) and myeloid markers (MPO, CD33 and CD13). Chromosomal analysis revealed a normal karyotype. To the best of our knowledge, this case represents the first report of the coexistence of granular ALL and hypereosinophilic syndrome.