Yellow arrows highlight a germinal center with lymphocyte proliferation.
Red arrows point to the lymphocytic infiltrate in which the germinal center is embedded. Blue arrow points to small atrophic follicles lined by Hurthle cells. The etiology of Hashimotos thyroiditis is unknown. It occurs most frequently in middle aged women. Commonly associated with other diseases of presumed autoimmune nature such as pernicious anemia, SLE and diabetes mellitus.