Acute myeloid leukemia (AML) with t(8;21)(q22;q22) generating the AML1/ETO fusion gene on 8q22 is a distinct type of AML t(8;21) category (WHO)/AML-M2 (FAB), generally associated with a favourable prognosis. Variant additional chromosomal abnormalities are frequently reported. We report three adult cases of this category with unusual karyotype. Bone marrow cytogenetics of case no. 1: 45,X,-Y, t(8;21)(q13;q22) with a novel breakpoint of chromosome 8 at (q13). Case no. 2: 46,X,t(X;2)(q22;q37),t(3;7)(q21;q36),t(5;14)(p15;q11),del(8)(q22) a complex rearrangement without the involvement of chromosome 21. Case no. 3: 49,XX,+5, t(8;21)(q22;q22), +16, +der(21)t(8;21)(q22;q22) with additional der(21). Endometrial in this case which was positive for myeloperoxidase (MPO) and CD117 conforming the AML infiltration. All are morphologically AML with t(8;21). Relevant literature in cytogenetic of AML-M2 is reviewed. The molecular mechanism involved in unusual rearrangements and clinical significance of them are subjected for further studies.
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