Thyroid incidentalomas. Prevalence by palpation and ultrasonography

BACKGROUND: Thyroid nodules are commonly identified on autopsy examination. There are relatively few descriptions, however, of the frequency with which thyroid nodules are encountered incidentally during the course of other investigations. METHOD: Prospective study to examine the prevalence of thyroid nodules in asymptomatic North American subjects, with palpation findings compared with findings on high-resolution ultrasonography. RESULTS: Palpable nodules were identified in 21 (21%) of 100 subjects, with nine solitary nodules (9%) and 12 multiple nodules (12%). In comparison, only 33 subjects were found to be free of any nodules by ultrasonography. Of the 67 subjects with abnormal ultrasound findings, 22 had solitary nodules (22%) and 45 had multiple nodules (45%). The prevalence of nodules was greater in women (72%) than in men (41%) (P < .02). A concordance rate of 49% was noted between ultrasound and findings by palpation. CONCLUSIONS: The data indicate that thyroid abnormalities are very common incidental findings, emphasizing the need for a conservative approach when such lesions are encountered incidentally.