Over a one month period, a 35 year old man develops symptoms of hypehyroidism with tachycardia and heat intolerance. Thyroid biopsy demonstrates a heavy mononuclear cell infiltrate with multinucleated giant cells, follicular disruption, and loss of colloid. About one month later,the patient develops symptoms of hypothyroidism. To which of the following is this patient's condition thought to be most closely related?

The patient has subacute thyroiditis, also known as granulomatous giant cell or de Quervain's thyroiditis. This condition is thought to be due to viral infection of the thyroid gland, and may follow an upper respiratory infection. Early in the process, the follicular destruction causes inappropriate release of thyroid hormone with resulting hypehyroidism. Later, the destruction can proceed to the point that hypothyroidism occurs. Antibodies that block the TSH receptor are a feature of Hashimoto's disease. Thyroid carcinoma usually does not produce hypehyroidism. Lymphoma of the thyroid is more likely to occur in the setting of Hashimoto's disease. Ref: Lal G., Clark O.H. (2010). Chapter 38. Thyroid, Parathyroid, and Adrenal. In F.C. Brunicardi, D.K. Andersen, T.R. Billiar, D.L. Dunn, J.G. Hunter, J.B. Matthews, R.E. Pollock (Eds), Schwaz's Principles of Surgery, 9e.