Diagnosis of acute myeloblastic leukemia with minimal differentiation – M0 according to FAB classification

Acute myeloblastic leukemia with minimal differentiation (M0 according to FAB classification):

• is about 5% of all ONL;
• blasts of medium size, with a delicate chromatin structure and 1-2 nucleols in the nucleus, no inclusions in the cytoplasm, basophilia of varying severity;

• blasts do not have morphological signs of differentiation;
• blasts contain myeloperoxidase, lipids and ASD-chloroacetate esterase in less than 3% of cells, a small amount of nonspecific esterase, PAS-positive substance in a diffuse form;
• blasts express myeloid antigens CD33, CD13, CD117, early hematopoietic antigens CD34, CD38, HLA-DR, react with MCA to peroxidase. They lack linearly specific T and B antigens;
• during ultrastructural cytochemical examination, peroxidase can be detected in small granules of the endoplasmic reticulum;
• loss of chromosomes 5 and 7, translocation (9; 22), additional chromosomes 13, 8 and 4, complex multiple rearrangements of the karyotype can be detected.

Acute myeloblastic leukemia without maturation (M1 according to FAB classification) – diagnostics

Acute myeloblastic leukemia without maturation (M1 according to FAB classification):

• makes up about 10% of all acute non-lymphoblastic leukemias (ONLL);
• in the bone marrow, the number of blasts exceeds 90% of the cells of the non-erythroid line;
• grit and / or Auer sticks can be detected in blasts;
• blasts contain myeloperoxidase, lipids, ASD-chloroacetate esterase in more than 3% of blasts, a small amount of nonspecific esterase, PAS-positive substance in a diffuse form;
• blasts express at least two myeloid antigens CD33, CD13 and / or react with MCA to peroxidase and with MCA CD34, specific lymphoid antigens are absent;
• in rare cases translocation can be detected (8; 21). In accordance with the WHO classification, these observations are categorized into an independent category of acute non-lymphoblastic leukemia (ONLL) with recurring anomalies.