Diffuse large B-cell lymphoma expresses CD45 and B-cell markers such as CD19, CD20, CD22, CD79a, and PAX-5. Monotypic immunoglobulin (surface or cytoplasmic) is variably present. Other positive markers include CD10 (40% cases), BCL6 (60% cases), and BCL2 (50% cases). CD5 is present in about 10% of cases. A small number of cases show post-germinal center or plasma cell-associated markers such as CD38, VS38, and MUM1. Ki-67 labeling is high (>20%). A minority of cases express CD30. Pan-T markers are negative. This flow cytometry image shows forward scatter (FS) vs CD19 plot. FS is proportional to the cell volume. High FS identifies a population of large cells (colored black). CD19 identifies them as B-cell lineage. The normal size lymphocytes are colored blue and red. Image courtesy of : Dr. Kali Freeman, Hematopathologist, Yosemite Pathology Medical Group, California, USA.