PMC9046630_01
Clonal evolution in a patient with CSF3R-T618I CNL to AML with t(4;12)(q12;p13). (A) Bone marrow aspiration smear showing maturing granulopoiesis without an increase in blasts at diagnosis (Wright-Giemsa stain, 1,000x original magnification). (B) Bone marrow aspiration smear showing blasts with small- to medium-size, round nuclei and a blocky chromatin pattern in agranular cytoplasm at AML transformation (left, Wright-Giemsa stain, 1,000x original magnification; right, peroxidase stain, x1,000 original magnification). (C) FISH analysis was performed using break-apart probes for the 4q12 region on cultured peripheral blood cells. The tri-color break-apart probe (5'FIP1L1 in green, 3'FIP1L1 5'PDGFRA in orange, and 3'PDGFRA in aqua) showed 1 triple fusion, 1 green-orange fusion (arrow), and 1 separate aqua signal (arrow), which confirmed CHIC2 or PDGFRA gene rearrangement (presumably translocation to derivative chromosome 12) in 58% of the nuclei.
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Bone marrow aspiration showed maturing granulopoiesis without an increase in blasts (Fig. 1A). Blasts possessed a blocky chromatin pattern but negative for myeloperoxidase activity (Fig. 1B). Fluorescent in situ hybridization (FISH) analysis using break-apart probes for the 4q12 region on cultured peripheral blood cells confirmed CHIC2 or PDGFRA gene rearrangement (presumably translocated to derivative chromosome 12) in 58% of nuclei (Fig. 1C).