Hashimoto's thyroiditis with elevated serum IgG4 concentrations is not equivalent to IgG4 Hashimoto's thyroiditis

Summary Background Hashimoto's thyroiditis ( HT ) with serum IgG4 concentrations greater than 135 mg/dL can be diagnosed as elevated serum IgG4 HT . HT can also be classified into IgG4 HT and non‐IgG4 HT based on an immunohistochemistry analysis of IgG4. The aim of our study was to determine the relationship between elevated serum IgG4 HT and IgG4 HT . Method Both thyroid tissues and serum samples stored before pathological examination from 93...