Moderate membraneous expression of CD21 is present on the neoplastic lymphocytes in this chronic lymphocytic lymphoma (CLL/SLL), and the benign follicular dendritic cells show strong membraneous expression.
Follicular dendritic cells within reactive follicles in this tonsil show strong membraneous staining for CD21. There is weak to moderate staining among the B-cells of the mantle zone.