Nodule size is an independent predictor of malignancy in mutation-negative nodules with follicular lesion of undetermined significance cytology.

Journal Article (Journal Article)

BACKGROUND: In thyroid nodule fine-needle aspiration (FNA) cytology, the atypia of undetermined significance or follicular lesion of undetermined significance (AUS/FLUS) category has a 5-15% malignancy risk that increases to 85-99% when mutation testing for BRAF, RAS, RET/PTC, or PAX8/PPARγ is positive. However, negative testing does not exclude malignancy. The study objective was to identify clinical and imaging features that predict cancer in mutation-negative AUS/FLUS thyroid nodules. METHODS: All patients were reviewed (April 2007 to April 2009) who had AUS/FLUS cytology, negative prospective molecular testing of FNA, and histopathology. RESULTS: Of the 230 nodules, 12 (5.2%) were malignant in 11 of 190 patients, and known clinical risk factors for thyroid cancer did not predict malignancy. On preoperative imaging, ≥1 suspicious ultrasound feature was identified in 33% of nodules and occurred regardless of histology (P = .23). Malignant mutation-negative AUS/FLUS nodules were larger than benign nodules (mean maximum diameter, 33.6 vs 24.0 mm; P = .007). On multivariate analysis, nodule size remained an independent predictor of malignancy (odds ratio, 1.043; P = .018). We observed no malignancies in 88 mutation-negative AUS/FLUS nodules <18.5 mm. CONCLUSION: Size is an independent predictor of malignancy in mutation-negative AUS/FLUS nodules and the risk increased 4.3% with every millimeter increase in nodule size. Selected patients with small, mutation-negative AUS/FLUS thyroid nodules may be managed with ultrasound surveillance in lieu of thyroidectomy.

Full Text

Duke Authors

Cited Authors

  • Mehta, RS; Carty, SE; Ohori, NP; Hodak, SP; Coyne, C; LeBeau, SO; Tublin, ME; Stang, MT; Johnson, JT; McCoy, KL; Nikiforova, MN; Nikiforov, YE; Yip, L

Published Date

  • October 2013

Published In

Volume / Issue

  • 154 / 4

Start / End Page

  • 730 - 736

PubMed ID

  • 24074409

Pubmed Central ID

  • 24074409

Electronic International Standard Serial Number (EISSN)

  • 1532-7361

Digital Object Identifier (DOI)

  • 10.1016/j.surg.2013.05.015


  • eng

Conference Location

  • United States