Comprehensive review of adult acute myelogenous leukemia: Cytomorphological, enzyme cytochemical, flow cytometric immunophenotypic, and cytogenetic findings

This study reports findings from a retrospective, comprehensive review of 8 0 cases of adult AML in regard to cytomorphology, enzyme cytochemistry (EC) , flow cytometric immunophenotyping (FCI), and chromosomal analysis. From t his review, we conclude that diagnostically challenging cases can only be s ubtyped by combining the cytomorphology with EC, FCI, and subsequent cytoge netic results. This is particularly true in recognizing the hypogranular va riant of AML,M3 (AML, M3m) and distinguishing it from other subtypes. Nonli neage expression of markers (CD1, CD2, CD4, CD5, CD7, and CD56) was nonspec ific as to AML subtype. af interest, CD2 coexpression in acute myelomonocyt ic leukemia with eosinophilia (M4-Eo) was exclusively associated with inver sion of chromosome 16 (inv 16) and was not observed in the other M4-Eo's wi thout inv16. We also recognized a previously undescribed M3m with CD56 coex pression, heightening awareness of this entity which needs to be distinguis hed from the unique subtype of CD56+ AML with otherwise similar immunopheno typic and morphologic characteristics. In addition, nonlineage expression o f CD19 alone was exclusively associated with the cytogenetic finding of t ( 8;21) (q22; q22) and thus may represent a favorable prognostic indicator by FCI. (C) 1999 Wiley-Liss, Inc.