Core‐needle biopsy versus repeat fine‐needle aspiration for thyroid nodules initially read as atypia/follicular lesion of undetermined significance

Background The purpose of this study was to evaluate the role of core‐needle biopsy (CNB) by comparing the results of CNB and repeat fine‐needle aspiration (FNA) for thyroid nodules that are initially read as atypia/follicular lesion of undetermined significance (AUS/FLUS) on FNA. Methods Among 2631 initial AUS/FLUS FNA results, 505 consecutive nodules (295 repeat FNAs and 210 CNBs) were retrospectively analyzed. The primary outcome was inconclusive (ie, nondiagnostic or AUS/FLUS). The secondary outcomes included inconclusive results of the subcategory, risk factors for inconclusive results, and diagnostic performance. Results CNB demonstrated significantly fewer inconclusive results than repeat FNA for the overall nodules (40.9% vs 63%; p < .001). Repeat FNA and group FLUS were significant risk factors for inconclusive results (odds ratio = 1.92; p =.001 and odds ratio = 2.08; p