RESUMEN
BACKGROUND: The impact of age, gender, and coexisting cold nodules on the frequency of thyroid carcinoma in hyperthyroid patients in an endemic iodine-deficient region was investigated. METHODS: The medical records of 817 patients who underwent operations for Graves' disease (GD) (n= 342), toxic multinodular goiter (TMG) (n = 299), and toxic adenoma (TA) (n = 176) between January 1988 and April 2006 were reviewed. RESULTS: Cold nodules were found in 293 (36%) of the patients, and 524 (64%) patients had no cold nodules. The incidence of thyroid carcinoma was 6.5% (53/817).The frequency of carcinoma was 3.8% in GD, 6.4% in TMG, and 12% in TA. The frequency of carcinoma in older patients (>/=50 years) was significantly higher than in younger patients (10.2% vs 4.3%, P = .001). The presence of cold nodules significantly increased the frequency of carcinoma (13% vs 2.9%, P = .001). A tumor was discovered within a cold nodule in 45% of the patients with thyroid carcinoma. CONCLUSION: Cold nodules are frequent in hyperthyroid patients in endemic iodine-deficient regions. Older patients (>/=50 years) and cold nodules are significant risk factors for malignancy in patients with hyperthyroidism. Surgical treatment may be suitable for those particular patients if malignancy can not be excluded.