Hürthle cell metaplasia on fine-needle aspiration biopsy is not by itself an indication for thyroid surgery

IntroductionThe aim of this study was to assess the malignancy rate in patients with Hürthle cell metaplasia (HCM) on fine-needle aspiration biopsy (FNAB).MethodsThe pathology results of patients with benign colloid (BC) and HCM on FNAB were compared using a prospective database.ResultsOne hundred fifty-three (65%) patients had BC on FNAB, and 82 (35%) had HCM. The mean nodule size was similar in both groups (25 ± 2 mm vs 26 mm ± 2 mm, P = .83). Malignancy was identified on the final pathology report in 21 (14%) versus 13 (16%) patients in the BC and HCM groups, respectively (P = .66). Of the patients with malignancy, the tumor was determined as microcarcinoma in 76% in the BC groups versus 85% in the HCM group (P = .48) and as incidental in 71% versus 85% (P = .39).ConclusionsA result of HCM on FNAB carries a similar rate of malignancy as BC and should not be treated differently. Most of the malignancies found were incidental microcarcinomas.