PMC6581877_01
Bone marrow morphology demonstrating hypercellularity (70-80%) with infiltration of myeloid blasts and suppression of normal hematopoiesis.
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A bone marrow biopsy showed a cellularity of 70-80% with diffuse infiltration by blasts and suppression of normal hematopoiesis (Fig. 1).
Myeloid blasts with pronounced cytoplasmic tails (hand-mirror blasts).
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Blasts showed monocytic features with a variable proportion of the cells displaying "hand-mirror" morphology with pronounced cytoplasmic tails and blebs (Fig. 2).
Cytogenetic analysis demonstrating 46, XY, der(1)t(1;19)(p13;p13.1) karyotype.
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All 22 metaphases analyzed revealed the presence of a derivative chromosome 1 resulting from an unbalanced translocation of the short arm of chromosome 19 proximal to 19p13 to the short arm of chromosome 1 at band 1p13: 46, XY, der(1)t(1;19)(p13;p13.1)[22] (Fig. 3).
Fluorescent in situ hybridization demonstrating unbalanced translocation of chromosome 1 band p13 and the short arm of chromosome 19 band p13 resulting in an extra copy of the E2A gene.
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Translocation, Dual Fusion Probe showed the translocation resulted in an extra copy of the E2A gene (19p13.3) on the derivative chromosome (Fig. 4). In this case, since there is gain of an extra E2A gene due to the unbalanced translocation, 2R3G signal pattern was evident by FISH (Fig. 4). DAPI images of the metaphases revealed that this extra E2A gene copy was on the short arm of chromosome 1 at band 1p13 (Fig. 4).
FISH analysis demonstrating an extra copy of the 5'MLL (11q23.3) gene. .
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In addition, an extra copy of the MLL (11q23.3) gene was also identified (Fig. 5).