PMC6883488_01
(A) Morphologic changes of BM smear and biopsy showed trilineage hypercellularity at initial onset. (B) Cervical lymph node biopsy with infiltration of T lymphoblasts. (C) BM smear showed markedly increased abnormal blasts and BM biopsy showed diffuse hyperplasia of immature cells at leukemic stage. (D) Flow cytometry analysis showed three separate clonal populations in BM sample. (E) G-banding karyotype of the bone marrow (BM) cells demonstrated the t(8;13)(p11.2;ql2.l); t(l;l4)(q42;q12) and trisomy 21. Arrows show the abnormal chromosomes. FISH analysis of BM cells (F) and lymph nodes (G) with an FGFR1 break-apart DNA probe revealing FGFR1 rearrangement (the 5'FGFR1 is labeled green, the 3'FGFR1 is labeled red).
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F1
Further bone marrow (BM) evaluation showed hypercellularity with trilineage growth including prominent granulocytic, erythroid and megakaryocytic proliferation (Figure 1A). TdT(+) CD99(+) CD4(+) Ki67(70%), while few scattered cells were positive for MPO, CD117 and CD8 (Figure 1B). Intriguingly, bone marrow aspirate revealed hypercellularity with predominant blasts (Figure 1C) and flow cytometry showed three separate clonal populations (Figure 1D): (1) The majority of blasts were cells with ambiguous lineage (P3 group, 41.9%), mainly expressed CD33, CD34, CD13, HLA-DR, CD123; partially expressed CD117, CD22, CD19, CD10, cCD79a, and MPO. (2) The myeloid subset (P6 group, 27.6%) mainly expressed CD33, CD13, HLA-DR, CD123, CD4, CD11c and partially expressed CD14 and CD22. (3) The B-lymphoblast subset (P7 group, 4.2%) mainly expressed CD34, CD19, CD22, CD10, cCD79a, HLA-DR and partially expressed CD33 and CD13. Karyotyping analysis of BM sample illustrated as 47, XY, t(1;14)(q42;q12), t(8;13)(p11.2;q12), +21 [20] (Figure 1E) and fluorescence in situ hybridization (FISH) analysis using the FGFR1 break-apart probe confirmed the presence of the FGFR1 rearrangement in all metaphase cells scored (Figure 1F). Interestingly, FGFR1 rearrangement was also detected in 36% (18/50) of cells in lymph node biopsy sample (Figure 1G).