RESUMEN
The microscopic slides of 16 patients who underwent bilateral subtotal thyroidectomy for hyperthyroid Graves' disease were reviewed and classified into three groups: I, Hashimoto's thyroiditis; II, Graves' disease; and III, both Hashimoto's thyroiditis and Graves' disease. Three patients were classified as group I, 10 as group II, and three as group III. In 38% of the patients with clinical Graves' disease the histologic evidence of Hashimoto's thyroiditis could be found either alone or in combination with histologic evidence of Graves' disease (groups I and III). One patient in group I, four in group II, and three in group III had infiltrative ophthalmopathy (50% of total). Hyperthyroid Graves' disease, Graves' ophthalmopathy, and Hashimoto's thyroiditis can occur all together, in duads, or individually at a specific time in a patient's life.