Fig. 3From: Diagnostic dilemma of IgG4-related primary localized cervical lymphadenopathy associated with aberrant IL-6 expression level a, b Histopathological specimens revealed lymphatic follicles (arrowhead) with an enlarged and hyperplastic germinal center. c, d The specimens were immunoreactive against both CD3 and CD20. e, f Immunohistochemical staining of IgG and IgG4 revealed a ratio of IgG4/IgG-positive plasma cells (arrowhead) of approximately 50 % and large quantities of IgG4 were noted in the germinal centerBack to article page