Unraveling enigmatic peripheral blood findings in a rare case of gamma-delta T-cell acute lymphoblastic leukemia

Figure 1. (A) Abnormal lymphoid cells in peripheral blood showing small size and relatively condensed chromatin, 100x magnification. (B) Bone marrow aspirate showing evident blast morphology of the cells, 100x magnification. Abnormal T-cells were strongly positive for CD99 (C), and partially positive for TdT (D), 20x magnification. PAX5 was used to confirm that the pattern of distribution of TdT+ cells was different from B-cells (picture not shown).

Figure 2. The neoplastic T-cells are shown in blue. They variably expressed CD45 (A) and were positive for cCD3 with only a small subpopulation expressing TdT (B). The CD3+ cells were dimly positive for CD8 and negative for CD4 (C). They expressed gamma delta (TCRγδ) (D), while negative for CD2 and immature markers including CD1a, CD34, and CD117 (E,F).