Lymphoma of the thyroid mimicking thyroiditis in a patient with the acquired immune deficiency syndrome.

A 35-year-old man with AIDS and a history of a remission from the lymphoma of the right tonsil (previously treated with chemotherapy and radiation) presented with a variety of clinical, laboratory and radiological findings strongly suggestive of subacute thyroiditis. Fine needle aspiration biopsy failed to establish the tissue diagnosis. Pathological examination of the thyroid tissue obtained during an open surgical biopsy revealed a lymphoma. Appropriate chemotherapy produced a rapid clinical and laboratory improvement manifested by the reduction of the goiter and restoration of a euthyroid state. Hypothyroidism subsequently developed, but therapy with thyroid hormone resulted in a rapid normalization of thyroid function tests. The patient expired because of AIDS-related complications.