Near-tetraploid acute myeloid leukemias: an EGIL retrospective study of 25 cases

Near-tetraploid acute myeloid leukemias (NT-AML) constitute an unusual presentation defined by blasts containing 80–104 chromosomes without aberrant near-diploid metaphases. Only about 60 NT-AML cases have been described so far in the literature.1 Reported cases where detailed information was available can be classified as M2 AML with duplication of t(8;21)(q22;q22) (N=13),1, 2 acute promyelocytic leukemias (M3 AML) with duplication of t(15;17)(q22;q21) (N=4)1, 3 – both categories reported mostly from Asian patients – or acute erythroleukemias M6 AML (N=7)1 and M0-M5 AML putatively originating from pluripotent myeloid progenitors characterized by erythroblastic and/or megakaryocytic (EM) dysplasia (N=17).4 Near-tetraploid blast cells are characterized by their large size on bone marrow smears,2, 3, 4 but individual chromosomal abnormalities are often difficult to analyze because of their 'fuzzy appearance'.1, 4