Immunohistochemical staining was strongly positive for CD45, CD20 (most positive) and TdT (Figure 1D, x40 objective); positive for paired box 5 (PAX5), CD19, CD79a, CD10, multiple myeloma 1; and negative for B‐cell lymphoma 2 (BCL2), BCL6, CD5, cyclin D1, CD1a, CD99, CD117, CD34, MPO and light chains. This evidence concerns the gene PAX5 and plasma cell myeloma.