Intraoperative Frozen Section in "Suspicious for Papillary Thyroid Carcinoma" after Adoption of the Bethesda System.

OBJECTIVE To evaluate the accuracy and utility of intraoperative frozen section examination (iFSE) in patients with a preoperative fine-needle aspiration (FNA) cytology of "suspicious for malignancy" (SFM)-Bethesda V, after the adoption of the Bethesda System for Reporting Thyroid Cytopathology. STUDY DESIGN Case series with chart review. SETTING Tertiary medical center. SUBJECTS AND METHODS All patients with SFM-Bethesda V who underwent thyroid surgery with iFSE between 2010 and 2015 were included. In cases where the iFSE was reported to be malignant, a total thyroidectomy was performed; otherwise, thyroid lobectomy (hemithyroidectomy) was performed. RESULTS The current series included 47 patients diagnosed preoperatively with FNA cytology of SFM-Bethesda V. The malignancy rate was 74.5% (35 of 47). Twenty-four patients with nonmalignant iFSE results underwent lobectomy during their initial surgery: 12 were subsequently found with benign final histology and did not undergo completion thyroidectomy; the other 12 patients had malignant results on final histology, but only 4 of them underwent completion thyroidectomy. iFSE resulted in a sensitivity and specificity of 65.7% and 100%, respectively, with a positive predictive value of 100% (23 of 23) and a negative predictive value of 50% (12 of 24). Accuracy of the iFSE methodology was 74.5% (35 of 47). CONCLUSIONS With no significant preoperative clinical or sonographic predictors for thyroid malignancy and given the high specificity of iFSE, our results support the use of iFSE for patients with preoperative FNA cytology of SFM-Bethesda V who are undergoing thyroid surgery, to determine the extent of required surgery.