Acute non-lymphoblastic leukemia differentiate
M5a acute nonlymphoblastic leukemia is differentiated from leukemias of the M0, Ml and M7 variants, as well as from acute lymphocytic leukemia. In these cases, the leading criteria are cytochemical and immunophenotypic parameters. A specific feature of monoblasts M5a and M5b is α-naphthyl acetate esterase, which is inhibited by sodium fluoride. Acute monoblastic leukemia with maturity is also differentiated from atypical promyelocytic leukemia without grain. Characteristic cytochemical markers (non-specific esterase and peroxidase) make it easy to distinguish them.
In the differential diagnosis of M6 and other variants of acute non-lymphoblastic leukemia, it is necessary to take into account the possibility of two subvariants of the disease: with the presence of an extended pathological red sprout (erythromyelosis) and with total bone marrow metaplasia with leukemic erythroblasts (erythroid leukemia).
In the first case, differentiated from RAIB MDS. If the number of erythroid progenitors is more than 50%, then the number of blasts should be recalculated to the non-erythroid fraction. In the event that the number of blasts exceeds 20%, M6 is diagnosed with acute non-lymphoblastic leukemia, in the opposite – RIBS MDS. If dysplasia is expressed in more than 50% of myelopoiesis cells, then, at the suggestion of the WHO classification, a variant of acute non-lymphoblastic leukemia with multilinear dysplasia is diagnosed.
In erythroleukemia, differential diagnosis is carried out with megakaryoblastic and lymphoblastic leukemias. The presence of erythroid erythroblasts (NAE3, NAE9, glycophorin A) and the absence of megakaryocytic and lymphoid antigens are taken into account.
Megakaryoblastic leukemia is distinguished from M0 and M6 in acute non-lymphoblastic leukemia based on the expression of specific antigens (CD41 and CD61). It should be noted that leukemic megakaryoblasts sometimes differ in some morphocytochemical features, which indirectly can suggest the need for advanced immunophenotypic studies. Thus, the irregular shape of the cells, the presence of outgrowths of the cytoplasm, its pronounced basophilia, the presence of megakaryocytes in the blood and their nuclei suggest a megakaryoblastic variant of acute non-lymphoblastic leukemia.
In addition, megacaryoblastic leukemia is differentiated from acute panmielosis with myelofibrosis. The presence of more than 50% of blasts expressing specific antigens, and the absence of trilinear myeloid cell dysplasia, make it possible to diagnose acute megakaryoblastic leukemia, even with fibrosis.