any of many inflammatory diseases of the thyroid gland. Several nonspecific types of thyroiditis, both acute and chronic, may be caused by bacterial and viral organisms. There are, however, two specific, noninfectious types of thyroiditis: (1) Hashimoto's disease (Hashimoto disease) (q.v.), or struma lymphomatosa, and (2) granulomatous thyroiditis (q.v.), sometimes referred to as giant cell thyroiditis, pseudotuberculous thyroiditis, or de Quervain's thyroiditis. A very rare chronic thyroid inflammation is Riedel thyroiditis (q.v.), or struma fibrosa.