Introduction THE APPROPRIATE diagnostic evaluation and therapy of the patient with a solitary, nonfunctioning thyroid nodule remains controversial despite many cases [over 50,000 operations for suspected thyroid cancer per year (1)] and studies. Because only a minority of such nodules are malignant, a number of techniques have been proposed to identify patients with a low likelihood of malignancy, making it possible in these cases to defer surgery or to avoid it altogether. Thus, several alternative approaches to the initial management of a cold nodule have been advocated: 1) immediate surgical removal (2–10); 2) a trial of thyroid suppression for 3 to 6 months with subsequent surgical removal of nodules that do not regress and with continued suppression of nodules that do shrink (11–13); 3) suppression with thyroid hormone with only rare patients recommended for surgery (14); and 4) fine needle aspiration and cytologic examination with suspicious or malignant cells being indications for surgery (15–22).