Progressive systemic sclerosis and Graves' disease. Report of three cases.

Progressive systemic sclerosis (PSS) is associated with a broad spectrum of autoimmune thyroid diseases. While an association between PSS and hypothyroidism is well established, a relationship between PSS and hyperthyroidism is less well defined. We treated three patients with PSS whose course was complicated by Graves' disease. Because hyperthyroidism can simulate many of the symptoms of PSS progression and treatment of hyperthyroidism can lead to resolution of clinical deterioration in such patients, it is important to recognize the simultaneous occurrence of these diseases.