A clonal expansion of myeloid blasts in the bone marrow, blood or other tissues. The classification of acute myeloid leukemias (AMLs) encompasses four major categories: 1) AML with recurrent genetic abnormalities 2) AML with multilineage dysplasia 3) Therapy-related AML 4) AML not otherwise categorized. The required bone marrow or peripheral blood blast percentage for the diagnosis of AML has been recently reduced from 30% (French-American-British [FAB] classification) to 20% (WHO classification). (WHO, 2001) -- 2003
