MSH: Inflammatory disease of the THYROID GLAND due to autoimmune responses leading to lymphocytic infiltration of the gland. It is characterized by the presence of circulating thyroid antigen-specific T-CELLS and thyroid AUTOANTIBODIES. The clinical signs can range from HYPOTHYROIDISM to THYROTOXICOSIS depending on the type of autoimmune thyroiditis.,CSP: diffuse infiltration of the thyroid gland with lymphocytes, resulting in diffuse goiter, progressive destruction of the parenchyma and hypothyroidism.,NCI: An autoimmune disorder caused by the production of autoantibodies against thyroid tissue. There is progressive destruction of the thyroid follicles leading to hypothyroidism.,NCI: An autoimmune condition of the thyroid gland (a gland located beneath the larynx). It is caused by the formation of antibodies that attack the thyroid gland and it usually causes hypothyroidism (too little thyroid hormone). Symptoms include fatigue, weight gain, constipation, dry skin, depression, and the inability to exercise.