An unusual case of acute myeloid leukemia with t(8:21) presenting with hypereosinophilia showing dysplastic features

Acute myeloid leukemia (AML) with specific genetic abnormalities is a clinically, biologically, and prognostically distinct category with some of the entities in it displaying characteristic morphology. AML with t(8:21) is one such subtype carrying favorable prognosis with specific blast morphology. Eosinophilia, characteristically, has been described till date in AML with inv (16); however, hypereosinophilia with prominent dysplastic features has yet not been seen with any AML subtype. We report the case of an 8-year-old child presenting with massive splenomegaly, hypereosinophilia, and low marrow blast percentage. The initial clinical and hematological impression was that of a chronic myeloproliferative neoplasm, which was later diagnosed as AML with t(8:21) with the help of cytogenetic studies. The case report highlights the unusual and extremely rare presentation of this AML subtype and the importance of cytogenetic studies in definite categorization, especially in cases with overlapping morphological and immunophenotypic findings.