IgG4-related lymphadenopathy (type III). (a) The lymph node shows interfollicular expansion with normal to small germinal centers. (b) Hypervascular proliferation is seen in the interfollicular zone. (c) A mixed infiltrate of small lymphocytes, immunoblasts, immature plasma cells, mature plasma cells, and scattered eosinophils is observed (d) Numerous IgG4+ cells are present in the interfollicular zone.
