Progressively transformed germinal centers is a benign condition of unknown pathogenesis characterized by a distinctive variant form of reactive follicular
hyperplasia in lymph nodes. We recently reported Ig G4-related disease in progressively transformed germinal centers. However, no large case series has been reported and clinicopathologic findings remain unclear. Here, we report 40 Japanese patients (28 men, 12 women; median age, 56 years) with progressively transformed germinal centers of the lymph nodes who fulfilled the histological diagnostic criteria for
IgG4-related disease (
IgG4(+) progressively transformed germinal centers), with asymptomatic localized
lymphadenopathy involving the submandibular nodes in 24, submandibular and cervical nodes in 14, cervical nodes only in 1, and cervical and supraclavicular nodes in 1. In all, 16 (52%) of 31 examined patients had allergic disease. Histologically, the lymph nodes demonstrated uniform histological findings, namely marked follicular
hyperplasia with progressively transformed germinal centers, and localization of the majority of
IgG4(+) plasma cells in the germinal centers. Serum
IgG4, serum
IgE and peripheral blood eosinophils were elevated in 87%, 92% and 53% of examined patients, respectively. Eighteen patients subsequently developed extranodal lesions (including five who developed systemic disease), which on histological examination were consistent with
IgG4-related disease.
IgG4(+) progressively transformed germinal centers presents with uniform clinicopathological features of asymptomatic localized submandibular
lymphadenopathy, which persists and/or relapses, and sometimes progresses to extranodal lesions or systemic disease. Nine patients were administered
steroid therapy when the lesions progressed, to which all responded well. We suggest that
IgG4(+) progressively transformed germinal centers should be included in the
IgG4-related disease spectrum.