Ultrasonography-Guided Core Needle Biopsy Did Not Reduce Diagnostic Lobectomy for Thyroid Nodules Diagnosed as Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance.

In this study, we evaluated the role of ultrasonography-guided core needle biopsy (US-CNB) in deciding upon management for prior atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) results. From May 2013 to June 2015, 149 thyroid nodules in 149 patients diagnosed as having AUS/FLUS were included. Of the 149 thyroid nodules, 86 (57.5%) had repeat US-guided fine needle aspiration (US-FNA) and 63 (42.3%) had US-CNB. Histopathology results were divided according to various indications for diagnostic lobectomy, and rates of diagnosis that are candidates for diagnostic lobectomy were compared. Of the 149 thyroid nodules included, 86 (57.7%) were diagnosed as benign, 27 (18.1%) as malignancy, and 36 (24.2%) as inconclusive. Repeat US-FNA had significantly higher rates of inconclusive diagnosis compared with US-CNB, 33.7% to 11.1% (P = 0.003). Nodules with US-CNB had significantly higher rates of surgery or follow-up, whereas those with US-FNA had higher rates of repeated biopsy (P < 0.001). Rates of cytopathologic candidates for diagnostic lobectomy did not show significant differences between repeat US-FNA and US-CNB for any of the indications (all P > 0.05). Based on this, we concluded that US-CNB has higher diagnostic rates than did repeat US-FNA, but it does not provide superior guidance over repeat US-FNA in deciding upon diagnostic lobectomy for thyroid nodules with prior AUS/FLUS cytology results.