PMC9489803_01
The bone marrow aspirate. The bone marrow aspirate smears were hypercellular, with massive (66%) infiltration by myeloblasts. The myeloblast varied in diameter between 12-16 mum, and had round nuclei with one to four nucleoli and fine nuclear chromatin. The cytoplasm was scanty, moderately basophilic, often containing azurophilic granules and sporadic Auer rod or pseudo-Chediak-Higashi inclusion. The proportion of promyelocytes was also elevated (9%), often having atypically shaped nuclei and granulation defects. More mature granulocytes were also often dysplastic - hypogranularity, agranularity, and unusually small myelocytes as well as pelgeroid changes were present. Erythropoiesis and megakaryopoiesis almost were absent.
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Erythropoiesis and megakaryopoiesis were almost absent (Fig. 1).
A. Routine cytogenetic analysis. Routine cytogenetic analysis revealed complex chromosomal changes involving three chromosomes: 8, 10, and 21. B. FISH analysis. Using a dual-color, dual-fusion RUNX1-RUNX1T1 probe revealed a specific RUNX1-RUNX1T1 fusion signal on the derivative chromosome 8.
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M-FISH analysis using a multi-color 24XCyte probe confirmed the results of routine chromosome analysis and revealed that part of the chromosome 8 material was translocated to chromosome 10, part of chromosome 10 moved to chromosome 21, and part of chromosome 21 was attached to chromosome 8 (Fig. 2A and 2B).
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