FAB-classification of acute leukemias and myelodysplastic syndromes

The FAB-classification was developed in 1976 and is based on cytologic and cytochemical criteria for acute myeloid and lymphatic leukemias as well as myelodysplastic syndromes. FAB stands for French-American-British because it was group of French, US-American and British hematopathologists who developed this classification. The FAB-classification was replaced by the WHO-classification. Occasionally, it is still used for acute myeloid leukemias since it can be helpful in observing morphological aspects in the course of treatment.

Acute myeloid leukemias

AML M0 acute myeloblastic leukemia, minimally differentiated
AML M1 acute myeloblastic leukemia, without maturation
AML M2 acute myeloblastic leukemia, with granulocytic maturation
AML M2 baso acute basophilic leukemia
AML M3 acute promyelocytic leukemia
AML M3v acute promyelocytic leukemia, microgranular variant
AML M4 acute myelomonocytic leukemia
AML M4 eos acute myelomonocytic leukemia together with bone marrow eosinophilia
AML M5a acute monoblastic leukemia
AML M5b acute monocytic leukemia
AML M6 acute erythroid leukemias
AML M7 acute megakaryoblastic leukemia

Acute lymphoblastic leukemias

ALL L1 acute lymphoblastic leukemia with small cells
ALL L2 acute lymphoblastic leukemia with medium sized cells
ALL L3 acute lymphoblastic leukemia with large cells

Myelodysplastic syndromes

RA refractory anemia
RARS refractory anemia with ringed sideroblasts
RAEB refractory anemia with excess of blasts
CMML chronic myelomonocytic leukemia
RAEB-T refractory anemia with excess of blasts in transformation