While distinguishing between T-lymphoblastic leukemia (T-ALL) and mature T-cell neoplasms is usually very straightforward with the presence of immature markers such as CD1a, CD34, and TdT in the former, there have been unusual cases of T-prolymphocytic leukemia, T-PLL seen with lack of surface CD3 and CD45 that can make the diagnosis more difficult (26, 27). Here, CD1A is linked to T-cell and NK-cell neoplasm.