Thyroid Nodules

Thyroid nodules are a common clinical problem presenting to both endocrinologists and general practitioners. Palpable thyroid nodules are found in 4% to 7% of U.S. residents [1,2]. A large population-based study in Framingham, Massachusetts, reported palpable nodules in 6.4% of females and 1.5% of males [3]. Autopsy studies, however, report much higher rates of thyroid nodules approaching 50% [4]. With the introduction of more sensitive imaging techniques, nonpalpable thyroid nodules are identified in patients with no prior history of thyroid disease. It is reported that incidental nodules found by ultrasound show a much larger prevalence of 19% to 67% [5]. The discovery of a thyroid nodule imparts concern for underlying malignancy, although only 5% to 10% of nodules harbor neoplastic cells [1,6]. The American Cancer Society projects that approximately 30,000 new cases of thyroid cancer will be diagnosed in 2006 and 75% of these cases will be in women [7]. Differentiated thyroid cancer carries a good prognosis, with a 5-year survival of 97%.