Figure 3

IgG4-associated marginal zone lymphoma.

The diffusely proliferating small- to medium-sized lymphoid cells [(A,B) case 26] are CD20⁺ (C) and CD3⁻ (D). Infiltration of many IgG⁺ (E) and IgG4⁺ (F) cells are observed, but these cells are polytypic (G) (Igκ) and (H) (Igλ). The IgG4⁺/IgG⁺ cell ratio is >40%.