Nodular Thyroid Disease: Natural History of Nodules Without an Initial Indication for Cytology

We investigated the evolution of thyroid nodules ≤1 cm without suspicious ultrasonographic characteristics and hot nodules detected by 131I scintigraphy (that do not require cytologic evaluation) in patients who are at low risk for malignancy. A total of 148 patients with 290 nodules ≤1 cm without suspicious characteristics and 32 subjects with low thyroid stimulating hormone and 55 hot nodules were studied. Thirty-six of the 290 nodules ≤1 cm without suspicious characteristics exhibited growth during follow-up and were punctured. Cytology was interpreted as benign in 28 cases, insufficient in 6, indeterminate in 1, and suspicious of malignancy in another (papillary carcinoma). Ten patients with hot nodules were treated with radioiodine because of progression to hyperthyroidism. Twenty patients with 35 hot nodules were followed and none had significant nodule growth. Therefore, malignancy was observed in only 1 of 345 nodules (0.3%) without an initial indication for cytology. Cytology is not necessary in the case of nodules ≤1 cm that have no suspicious radiologic features or hot nodules in patients without a history of neck radiation during childhood or a family history of thyroid carcinoma.