LARGE CYSTIC SOLID THYROID-NODULES - A POTENTIAL FALSE-NEGATIVE FINE-NEEDLE ASPIRATION

Background. False-negative fine-needle aspiration (FNA) biopsy results of thyroid nodules are of particular concern because they imply missed malignant lesions. The purpose of this study was to identify characteristics of thyroid nodules that may lead to false-negative cytologic interpretation after FNA. Methods. We reviewed 90 consecutive patients who underwent preoperative FNA of thyroid nodules followed by thyroid surgery during a period of 27 months, including their clinical data, type and size Of thyroid nodule, FNA cytology results, and final pathology report of the surgical specimen. Results. Thyroid nodules that had the highest probability of malignancy were those that were large (3 cm or larger), cystic/solid, or large and cystic/solid. The overall false-negative rate for preoperative FNA was 11%. Large, cystic/solid, and thyroid nodules with both characteristics had false-negative rates of 17%, 25%, and 30%, respectively, compared with 0%, 9%, and 17% for small (less than 3 cm), solid, and solid nodules 3 cm or larger, respectively. Conclusions. Because of the high prevalence of malignancy in thyroid nodules that are large (3 cm or larger), cystic/solid, or large and cystic/solid and the high false-negative rate of FNA in diagnosing these lesions, thyroid lobectomy for diagnosis should be strongly considered in these patients even when FNA cytologic finding is interpreted as benign.