May-Grunwald-Giemsa stain of a bone marrow aspirate from a patient with RD (original magnification ×1000, immersion oil, Zeiss Axio Imager M1, AxioCam MRc [Carl Zeiss Microscopy, Jena, Germany]) showing immature lymphoid cells (hematogones) with slim cytoplasm as well as myeloblasts and a dysplastic promyelocyte with nuclear and cytoplasmic vacuoles. In the work-up of the bone marrow with immunostaining and flow cytometry, immature lymphocytes were identified as polyclonal B-cell precursors (flow cytometry of the bone marrow revealed a population of 46% with markers of pre–B cells CD10⁺/CD19⁺/cyIgM⁺/TdT⁺/CD34^–; clonality was tested in a multiplex polymerase chain reaction for the rearranged B-cell receptor heavy chains [data not shown]).