PMC6487276_01
Pathological features of a cutaneous tumor and microscopic features of blastoid cells in bone marrow. Skin biopsy showed diffuse infiltration of tumor cells with immunoblastoid cytology in the dermis (H-E staining: A, x 100; B, x 400). Immunohistochemically, the infiltrating immunoblastoid cells were positive for CD4 (C,  x 200), CD123 (D,  x 200), TCL1 (E,  x 200), and MYC (F,  x 400) and partly positive for CD56 (G,  x 200). Bone marrow aspiration showed the infiltration of medium-sized blastoid cells (May-Giemsa staining: H, x 1000).
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The cells were positive for CD4, CD123, TCL1, and MYC and partly positive for CD56 (Fig. 1A-G); but negative for CD3, CD20, CD79a, terminal deoxynucleotidyl transferase (TdT), myeloperoxidase (MPO), CD34, and the Epstein-Barr encoding region. Bone marrow examination showed 92% blast cells (Fig. 1H), of which MPO activity was not detected by the diaminobenzidine method.
Split fluorescence in situ hybridization assessment of a cutaneous tumor. Tumor cells were positive for an 8q24 (MYC locus) rearrangement using Vysis LSI IGH-MAF dual colour dual fusion translocation probe (A), but negative for SUPT3H (B) and MYB rearrangements (C).
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In split fluorescence in situ hybridization (FISH) assay, tumor cells were positive for 8q24 (MYC locus) rearrangement but negative for SUPT3H and MYB rearrangements (Fig. 2).