IgG4-positive Hashimoto thyroiditis and its association with IgG4-related sclerosing disease

Abstract

A woman in her 50s was referred with suspected thyroid malignancy and underwent total thyroidectomy. Immunohistochemical analysis revealed IgG4-positive Hashimoto's thyroiditis. IgG4-related thyroid disease is poorly understood, and thought to encompass various entities including IgG4-positive Hashimoto's thyroiditis, Fibrosing Variant of Hashimoto's thyroiditis, Reidel's thyroiditis and Graves' disease with elevated IgG4 levels. Furthermore, it may be associated with a systemic fibrosing condition called € IgG4-related sclerosing disease'. The clinical significance of IgG4-positive thyroid disease, however, remains unclear.