An examination of the changes in the thyroid gland of patients with exophthalmic goiter in whom a remission had been brought about by the administration of iodine led Rienhoff1 to suspect that a large percentage of benign nodules in the thyroid gland are caused by involutional irregularities, and a further study2 of microscopic sections from all the patients with nodular goiter operated on at the Johns Hopkins Hospital convinced him that his hypothesis was correct. He found that only about 8 per cent of thyroid nodules represent true neoplasms (adenomas), and that the remaining 92 per cent consist of thyroid tissue (usually encapsulated) in varying degrees of hypertrophy and hyperplasia, of involutional change and even of degeneration. In those cases which presented clinical evidence of hyperthyroidism, hypertrophy and hyperplasia were found, usually outside of the nodules and occasionally only in circumscribed areas.
The following study consists of a