Figure 3

Staining Pattern in Reactive Lymphoid Tissues. A: Low power view of tonsil showing polyclonal staining within germinal center and mantle zone, and scattered paracortical B cells as well as intra-germinal center and paracortical plasma cells (40×). B: High power view of germinal center demonstrating polyclonal centrocytes, centroblasts, and a few plasma cells (500×). C: High power view of medullary sinuses with polyclonal plasma cells (600×). D: High power view of reactive paracortical hyperplasia showing KAPPA restricted B-immunoblast (black arrow), LAMBDA restricted B-immunoblast (pink arrow), negatively staining presumed T-immunoblast (blue arrow), and negatively staining histiocyte (blue arrowhead) (1000×).