Malignancy outcomes and the impact of repeat fine needle aspiration of thyroid nodules with Bethesda category III cytology: A multicenter experience

Background The clinical management of Bethesda III category thyroid nodules has some undefined points and differs among centers and conflicting malignancy rates are present in the literature. The aim of this study was to investigate the Bethesda category III thyroid nodule outcomes in our centers, to determine malignancy rates and also to evaluate clinical and sonographic features which may help to predict malignancy. Methods This retrospective study included 333 patients with thyroid nodules who had Bethesda category III on fine needle aspiration (FNA) in three tertiary medical centers of Turkey. Results Among 333 patients, 302 had appropriate follow up. Eighteen patients received thyroidectomy after the first FNA, with a malignancy rate of 38.89% (7/18) and 284 patients received a second FNA. After the second FNA, thyroidectomy was performed in 80 patients and 41 patients needed the third FNA. Thirteen thyroidectomies were performed after the third FNA. Totally 111 patients received thyroidectomy with a malignancy rate of 48.65% (54/111) among patients with surgery and the lower bound was detected as 17.88% (54/302). Of these patients the malignancy rates of patients receiving thyroidectomy with two and three FNAs were 47.50% (38/80) and 69.23% (9/13), respectively. Hypoechogenicity, microcalcification, and irregular margin were found as good predictors for malignancy. Conclusion We demonstrated that the malignancy rate was 48.65% in patients receiving thyroidectomy. We showed a higher malignancy rate than the traditionally rate of 5%-15%. This study showed that repeat FNAs decrease the rate of unnecessary surgery performed for benign lesions by increasing the rate of malignancy detection.