Comprehensive Study of Thyroid Fine Needle Aspiration in Pediatric and Young Adults.

Introduction: Thyroid nodules are uncommon in the pediatric population, with a 1-1.7% prevalence. The Bethesda System of Reporting Thyroid Cytopathology (TBSTC) is a well-established thyroid fine needle aspiration (FNA) reporting system. While the TBSTC guides therapy for both adult and pediatric patients, the reported risk of malignancy (ROM) is variable in the literature. The aim of this study is to compare the ROM in pediatric age of <15 with. ≥15 years old.

Material and methods: We searched for patients aged 21 or younger who underwent FNA of thyroid nodules from 2016-2021. Data included patient demographics, nodule size, FNA results, molecular results, and surgical pathology follow-up. Patients were divided into two cohorts: 0-14 (<15) and 15-21 (≥15) years old.

Results: 145 nodules from 102 patients (26 cases in <15 and 94 in patients ≥ 15) were analyzed. Diagnoses and ROM were: non-diagnostic (n=3); benign (108, ROM 50%), atypia of unknown significance (n=13, ROM 67%), follicular neoplasm (n= 6, ROM 33%), suspicious for malignancy (n=1, ROM 100%), malignant (n=14 ROM 100%). No significant differences (p values ≥ 0.2) between the age groups were noted. Based on surgical follow-up results, the overall malignancy rate was 8% and 19% for <15 and ≥15 years old groups, respectively.

Conclusion: The ROM for thyroid nodules in the pediatric population is higher than in adults. There appears to be a trend towards a higher overall malignancy rate in patients aged 15-21 compared to those under 15, though this difference is not statistically significant. Further studies with larger patient numbers are required to determine if the ROM differs significantly between these age groups.