Bone marrow neoplastic

Bone marrow - neoplastic myeloid

AML not otherwise specified

AML with maturation (FAB AML M2)

Last author update: 1 February 2013
Last staff update: 22 September 2023

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PubMed Search: Acute myeloid leukemia with maturation (FAB AML M2)

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Cite this page: Mihova D. AML with maturation (FAB AML M2). website. Accessed February 22nd, 2024.
Definition / general
  • 10% of AML cases; 5% of childhood leukemias
  • Any age, 20% are < 25 years and 40% are 60 years+
  • Anemia, thrombocytopenia, neutropenia; variable number of blasts in peripheral blood
  • Variable prognosis
  • Criteria for diagnosis: 20%+ nonerythroid cells in peripheral blood or bone marrow are myeloblasts; monocytic precursors are < 20% in bone marrow and granulocytes are 10%+ of cells
  • Enzyme cytochemistry: most blasts are positive for myeloperoxidase or Sudan Black B, and chloroacetate esterase
Case reports
Microscopic (histologic) description
  • Usually hypercellular marrow
  • Full range of myeloid maturation through maturing neutrophils, often with abnormal segmentation and 10%+ bone marrow cells with variable degree of dysplasia
  • Auer rods in 70% of blasts; myeloblasts with or without azurophilic granules
  • Erythroid and megakaryocyte precursors may have dysplastic changes
  • Often increased eosinophilic precursors without cytological and cytochemical abnormalities of inv(16)(p13.1q22)
  • Basophils may be increased, rarely mast cell hyperplasia (Indian J Pathol Microbiol 2007;50:655)
Microscopic (histologic) images

AFIP images
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Bone marrow
biopsy: markedly

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Diagnosed as AML with maturation because no t(15;17) and no DIC but FISH not done, so may actually be acute promyelocytic leukemia

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Myeloperoxidase positive blasts

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Erythroid cells are negative

Bone marrow smears (Wright-Giemsa):
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Type III myeloblasts

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myelocytes and

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Several myeloblasts and maturing forms

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Pseudopods, cytoplasm and prominent Auer rods

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Several blasts have prominent nucleoli and Auer rods

Positive stains
Negative stains
Electron microscopy images

AFIP images
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Numerous primary granules and fusion of Auer rods

Molecular / cytogenetics description
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