Immunohistochemical analyses of the tumor. CD20-positive lymphoid cells surround abortive CD10-positive germinal centers. Scale, 200 μm or 50 μm, is indicated by bars in CD20 or CD10, respectively. About 10-20% of proliferating cells were CD5 positive lymphoid cells (T-cells), but the vast majority were not. CD21-positive follicular dendritic cells were structurally aligned around germinal centers. The germinal center is indicated by GC and dotted circles with a scale bar of 50 μm. Immunohistochemical analyses by cyclin D1, with a scale bar of 50 μm.