Fig. 4

Pathological findings of the excised lymph nodes: Histopathology showed various-sized lymphoid follicles and large nodular lesions with an enlarged mantle zone, and multiple germinal centres in single nodules (a). Proliferation of small blood vessels and marked eosinophilic infiltration were also observed between the nodes (b). Immunohistochemical staining of the germinal centres was positive for CD10 (c), negative for bcl-2 (d), and positive for bcl-6 (e). Staining was positive for IgG in the germinal centres and between nodes, and some areas were IgG4-positive (f)