THU222 Malignancy Risk In Nodules Classified As Atypia Of Undetermined Significance In A Predominantly Hispanic Free-standing Children’s Hospital

Disclosure: D. Baboun: None. N. Solano: None. A. Martinez Sanchez: None. C. Brathwaite: None. R. Restrepo: None. F. Alkhoury: None. A. Carrillo-Iregui: None. Background: During the last 3 decades, there has been an increase in pediatric thyroid cancer. Ultrasound-guided fine needle aspiration (US-FNA) of thyroid nodules continues to be the main modality for histopathological evaluation. Thyroid nodules reported as atypia of undetermined significance (AUS) present a challenge to clinicians in deciding on surgical intervention versus observation (1). Objective: The purpose of this study is to determine the rate of malignancy in cases classified as AUS in the predominantly Hispanic population treated at a free-standing children’s hospital. Methods: Upon Institutional Review Board approval, we performed a retrospective chart review from 2012-2022 of 211 patients who underwent US-FNAs of thyroid nodules. We analyzed demographics and histopathological diagnoses. Results: The majority of our population identified as Hispanic (80.10%). There were 167 (79.10%) females and 44 (20.90%) males, and the age range was 4-21 years. Two hundred eleven patients underwent a total of 232 US-FNAs. The Bethesda distribution is as follows: 29 (12.50%) nondiagnostic, 98 (42.24%) benign, 45 (19.40%) AUS, 21 (9.05%) follicular neoplasm, 9 (3.88%) suspicious, and 30 (12.93%) malignant. Of the AUS group, 33 of the 43 patients underwent surgery. Of the surgical specimens, 16 (48.48%) were malignant, and 17 (51.52%) were benign. Of the 10 patients who did not undergo surgery, 2 underwent a repeat US-FNA with benign results, 5 were monitored, and 3 did not return for a follow-up. Conclusions: In our experience, patients with US-FNAs classified as AUS have a rate of malignancy of 48.48%, which is consistent with the published rate of higher incidence in the pediatric population than in the adult population. Thus, our results support the current recommendation of surgical intervention rather than observation in these pediatric patients. Molecular markers are a useful tool for determining management of thyroid nodules in adults; however, further research in the pediatric population is needed to have standardized recommendations. Reference: (1) Rossi, E.D. et al., Cancer Cytopathology. 2017 Aug 125:594-603. Presentation: Thursday, June 15, 2023