Seven classes are described in the WHO classification, including AML with recurrent genetic abnormalities AML with myelodysplasia-related changes (AML-MRC) Therapy-related AML (t-AML) AML, not otherwise specified (NOS) Myeloid sarcoma Myeloid proliferations related to Down syndrome Blastic plasmacytoid dendritic cell neoplasm Morphologic criteria from the previous French-American-British (FAB) classification system are used for subtypes that are not otherwise specified (NOS).