Fig. 1

Case 1. Flow cytometric analysis of the marrow aspirate shows that the gated atypical lymphocytes express surface CD2 and CD56 but not CD3 or CD7 (a-c). In addition, they express cytoplasmic CD3 but not TdT, indicating an NK-cell phenotype. Marrow trephine shows a hypercellular marrow with extensive infiltration by small to medium-sized atypical lymphocytes (d and e, HE stains; original magnifications × 200 and × 1000, respectively). The tumor cells express cytoplasmic CD3 (f), TIA-1 (g) and EBER (h). Analyses of genomic copy number alteration using the HumanCytoSNP-12 Beadchip (Illumina). i and j, These two panels show evidence of gain of one copy at 4q21-q35 (i) and 9p24-p13 (j) respectively. B allele frequency (BAF) plot in both panels demonstrates an altered pattern of BAF (0.0, 0.33, 0.67 and 1.0), which is highlighted in a blue background. Log R ratio plot displays no apparent alteration and this is most likely due to the presence of mosaicism in the region of chromosomal gain