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AML  M1 (without Maturation)

AML without maturation (AML-M1) is defined as an acute leukemia with no significant myeloid maturation and ≥90% blast cells in the non-erythroid population. The myeloid origin of blast cells is confirmed by positive (≥3%) staining for MPO and/or Sudan Black B by cytochemical techniques, as well as expression of myeloid-associated markers by immunophenotypic analysis.

AML without maturation accounts for 10–15% of all AMLs and is rare in children. The prognosis is poor, particularly in those with marked leukocytosis and increased circulating blasts.

Blast morphology can be similar to that of AML with minimal differentiation, or can show basophilic cytoplasmic granulation or even Auer rods, but by definition at least 3% of blasts must show cytochemical staining for MPO or SBB(Sudan Black B).

flow cytometric studies reveal the expression of myeloid-associated markers, such as CD13, CD33, and/or CD117. CD34 and HLA-DR and cytoplasmic MPO are often positive. Monocytic-associated markers, such as CD11c and CD14, are usually negative. Also, cytoplasmic CD3, CD22, and CD79a are negative.

Immunohistochemical stains are negative for CD68, CD3, and CD20 but may show positive reaction for MPO in the blast population.

Cytogenetic aberrations are variable and include both numerical (aneuploidy) abnormalities and translocations. Trisomy 11, trisomy 13, and trisomy 14 as well as t(9;12)(q34;p13), t(11;19) (q23;p13), t(14;17) (q32; q11.2), der(12)t(12;17)(p13;q11.2), and der(16)t(16;20)(p13;p11.2) have been reported in this leukemic subtype [157, 166, 168, 169].






































Above case shows (blasts- red, lymp-green, grans-blue, monos-pink) positivity for CD34, MPO, CD33, CD13, CD117 HLA-DR, CD15  and negativity for CD7, CD65, CD15, CD64, CD14, CD19, HLA-DR, CD56, CD11b, CD38, CD36, cCD79a, cCD3, CD2




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