AML classification (WHO)
Classification of acute myeloid leukemia (World Health Organisation, 2008)
|AML with recurrent genetic abnormalities||Bone marrow or peripheral blood blasts ≥ 20%, or myeloid sarcoma, AND one of the following cytogenetic abnormalities:
|Therapy-related myeloid neoplasms||AML with history of treatment of an unrelated disorder with any of the following agents:
|AML with myelodysplasia-related changes||≥ 20% blood or marrow blasts and ANY of the following:
|AML, not otherwise specified||AML not meeting any of the above criteria. Categories are:
|Myeloid sarcoma||Tumor mass of myeloid blasts with or without maturation at an anatomical site other than the bone marrow (if meets any of the criteria above, categorise as the relevant AML with a myeloid sarcoma)|
- Complex karyotype (≥3 unrelated abnormalities, none of which are recorded in the AML with recurrent genetic abnormalities subgroup)
- Unbalanced abnormalities: -7/del(7q), -5/del(5q), i(17q)/t(17p), -13/del(13q), del(11q), del(12p)/t(12p), del(9q), idic(X)(q13)
- Balanced abnormalities: t(11;16)(q23;p13.3)*, t(3;21)(q26.2;q22.1)*, t(1;3)(p36.3;q21.1), t(2;11)(p21;q23)*, t(5;12)(q33;p12), t(5;7)(q33;q11.2), t(5;17)(q33;p13), t(5;10)(q33;q21), t(3;5)(q25;q34)
* these abnormalities most commonly occur in therapy-related disease, which must be excluded before using as evidence for AML with myelodysplasia-related features
This classification of acute myeloid leukemia (acute myelogenous leukemia) was published in the 4th edition of the World Health Organisation book, “WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues” in 2008.1
The diagnosis of acute myeloid leukemia is made when blasts account for ≥20% of nucleated cells in the bone marrow or peripheral blood. Acute myeloid leukemia may also be diagnosed with a lower percentage of blasts in the presence of certain genetic abnormalities (t(8;21), inv(16), t(16;16) or t(15;17)), or with myeloid sarcoma.
When applying the WHO classification, the categories highest in the table to the left take precedence over those lower in the table. For instance, AML following cytotoxic chemotherapy and with t(8;21) will be classified as “AML with t(8;21)”, and not as a “therapy-related myeloid neoplasm”. Similarly, AML arising after myelodysplastic syndrome but meeting the morphologic criteria for acute myelomonocytic leukemia will be classified as “AML with myelodysplasia-related changes”, and not as “acute myelomonocytic leukemia”.