Thyroid gland: US screening in middle-aged women with no previous thyroid disease.

To determine the prevalence of thyroid nodules in the healthy population, ultrasonography (US) of the thyroid gland was performed in 101 women aged 49-58 years in an urban area in southern Finland where goiter is not considered endemic. Subjects with any previous thyroid disease were excluded. Thyroid nodules or abnormalities of the echo structure were found in 36 (35.6%) subjects. Seventeen (47.2%) subjects had solitary nodules, 14 (38.9%) had multiple nodules, and five (13.9%) had diffuse abnormalities. Subjects with abnormal findings at US were further examined with fine-needle aspiration biopsy. Clinical examination and blood tests were performed for evaluation of levels of thyroxine, thyroid-stimulating hormone, and thyroid antibodies. One patient had a leukemic thyroid nodule, but no primary thyroid malignancies were found. In most cases, cytologic findings were benign and nonspecific, with a variable amount of degenerative changes. Three atoxic multinodular goiters and two cases of Hashimoto thyroiditis were detected. The results are in accordance with autopsy studies indicating that focal nodular changes of the thyroid gland are common in middle-aged women.