RESUMO
OBJECTIVE: To explore the phenotypic and genetic characteristics of acute megakaryoblastic leukemia (AMKL) in young children accompany by WT1, MLL-PTD and EVI1, in order to improve the diagnosis level of AMKL. METHODS: EDTA-K2 anticoagulation venous blood was collected for blood routine and morphological analysis of blood cells; bone marrow was extracted for cell morphology, immunophenotype, chromosome karyotype and fusion gene analysis. RESULTS: White blood cell count was 12.3× 109/L, hemoglobin was 73 g/L, and platelet count was 13× 109/L. The morphological analysis of blood cells showed that the size of immature cells was like that of primitive immature lymphocytes, which was circular or irregular and part of them with obvious pseudopodia. The cytoplasm is basophilic with heterogeneous coloration and granules. Nuclear chromatin is fine and even, 1-3 nucleoli can be seen, these immature cells account for about 40%; the morphology of bone marrow cells was consistent with acute leukemia, negative for peroxidase staining, negative for AS-DNCE staining and alpha-NBE staining. Flow cytometry results showed that the protocells account for about 52% and significant expression of megakaryocytes related markers (cCD41+, CD61+, CD36+). Chromosome karyotype is 46, XX, der(3) add(3)(p21)add(3)(q25), add (9)(q22), -13, +mar [4]/46, XX, del(13)(q12q22) [3]/46, XX[3]. The fusion gene WT1 was overexpressed, MLL-PTD and EVI1 were positive. CONCLUSION: Acute megakaryocytic leukemia has unique and complex phenotypic and genetics characteristics.