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).