This symmetrically small thyroid gland demonstrates atrophy. This patient was hypothyroid. This is the end result of Hashimoto thyroiditis. Initially, the thyroid is enlarged and there may be transient hyperthyroidism with Hashimoto thyroiditis, but this is followed by a euthyroid state and then hypothyroidism with eventual atrophy years later from progressive thyroid atrophy. Hashimoto thyroiditis results from abnormal T cell activation and subsequent B cell stimulation to secrete a variety of autoantibodies directed against thyroid.

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