Hyperthyroidism and concurrent thyroid malignancies.

In a 17-year period 1848 patients with hyperthyroidism were operated on. Fourteen (0.76%) had a coexisting thyroid malignancy. Preoperative scintiscan and pathologic diagnoses were compared: 10 malignancies were in cold nodules, two were unidentifiable preoperatively due to small size, and two were in hot areas. Five patients had papillary cancer, four follicular, three anaplastic, and two medullary. Patients with uninodular toxic goiter had a low rate of associated malignancy (0.27%, 3/1108). In contrast, patients with multinodular toxic goiter had an incidence of 1.63% (11/676). No patient with Graves' disease (n = 64) had a carcinoma. Extensive use of fine-needle aspiration biopsy enabled preoperative diagnosis in a majority of the cases (9/14, 64%). We conclude that the incidence of coexisting thyroid malignancy and hyperthyroidism is rare in our endemic iodine-deficiency goiter area.