Evaluation of Follow-up Examinations Using Ultrasonography for Patients With Thyroid Nodules Initially Diagnosed as Benign.

Background/aim: The aim of this study was to determine the natural history of benign thyroid nodules using ultrasonography.

Patients And Methods: The records of 223 patients with benign thyroid nodules treated at the Kochi Medical School from 2010 to 2012 were reviewed retrospectively. Repeated ultrasonography was performed, and the findings were directly compared with previous images.

Results: The median change in the size of the nodules was 0.01 cm/year, although the size of six nodules (2.7%) increased more than 0.5 cm/year, and these nodules were removed surgically. Nineteen patients (8.5%) underwent surgery during the follow-up period. Compared to those who did not undergo surgery, the size of the nodules was larger and the rate of change in nodule diameter was higher in those undergoing surgery. The pathological diagnosis based on repeated fine needle aspiration cytology was benign nodules in 16 patients and papillary cancer in three patients.

Conclusion: Even if a thyroid nodule is initially diagnosed as benign, it may have malignant potential. Therefore, so as not to miss malignancies, nodules should be carefully re-evaluated to assess their growth or change in size using ultrasonography.