A meta‐analytic review of the Bethesda System for Reporting Thyroid Cytopathology: Has the rate of malignancy in indeterminate lesions been underestimated?

The AUS category was characterized by limited reported follow-up and surgical outcome. The data demonstrated that FNAs with an AUS diagnosis had a higher risk of malignancy than the risk according to published TBSRTC criteria, whereas the percentage of malignancy in FNAs with an FN/SFN diagnosis did not differ from that according to TBSRTC. Hurthle cell lesions represent a challenging category, underlying the importance of further studies to define whether they can be diagnosed in the AUS/FLUS category rather than the FN/SFN category.