Color Atlas of Hematology - Practical Microscopic and Clinical ...

94Abnormalities of the White Cell SeriesChromosome analysis provides important information. In practice,however, the diagnosis of acute leukemia is still based on morphologicalcriteria.However, where the possibilities of modern therapeutic and prognosticmethods are fully accessible, new laboratory procedures based on geneticand molecular biological testing procedures form part of the diagnosticwork-up of AML. The current WHO classification takes account of thesenew methods, placing genetic, morphological, and anamnestic findings ina hierarchical order (Table 15).According to the new WHO classification, blasts account for more than20% of cells in acute myeloid leukemia (in contradistinction to myelodysplasias).Table 15WHO classification of AMLAML with specificcytogenetic translocationsAML with dysplasia inmore than 1 cell line(2 or 3 cell linesaffected)*Therapy-induced AMLund MDSAML that does not fitany of the other categories– With t(8;21) (q22; q22), AML 1/ETO– Acute promyelocytic leukemia (AML M3 with t(15;17) (q22;q11-12) and variants, PML/RAR-α– With abnormal bone marrow eosinophils and (inv16)(p13;q22) or to t(16;16) (p13; q22); CBFβ/MYH 11– With 11q23 (MLL) anomalies– With preceding myelodysplastic/myeloproliferative syndrome– Without preceding myelodysplastic syndrome– After treatment with alkylating agents– After treatment with epipodophyllotoxin– Other triggers– AML, minimal differentiation– AML without cell maturation– AML with cell maturation– Acute myelomonocytic leukemia– Acute monocytic leukemia– Acute erythroid leukemia– Acute megakaryoblastic leukemia– Acute panmyelosis with myelofibrosis– Myelosarcoma/chloroma– Acute biphenotypic leukemia*** The dysplasia must be evident in at least 50% of the bone marrow cells and in 2–3 cell lines.** Biphenotypic leukemias should be classified according to their immunophenotypes. Theyare grouped between acute lymphocytic and acute myeloid leukemias.