French American British
Degree of maturation
Lineage of the leukaemic blasts
No evidence of myeloid differentiation by
morphology and light microscopy.
Immunological markers are required.
Any age but most common in infants and older
Medium sized blast cells with dispersed
Round to indented nuclei.
1 or 2 nucleoli.
<3% are SBB/MPO +
CD34,CD33, HLA-DR +
AML M 1
>90% blast cells without significant evidence
of maturation to more mature neutrophils.
Any age usually adults
>20% blasts with evidence of maturation
(>10% maturing cells of neutrophil lineage).
AML M 5
Acute Monocytic Leukaemia
80% or more of the leukaemic cells are
monocytic lineage ( monoblasts,
promonocytes and monocytes)
Organ involvement (CNS, Gum hyperplasia,
Nonspecific easterase +
Dyplastic erythroid precursors
>50% erythroid precursors in the entire
nucleated cell population and >20%
myeloblasts in the non-erythroid cell
Acute Megakaryoblastic Leukaemia
20% blasts of which at least 50% are of
Cytopenias often thrombocytopenia