The Bethesda System for Reporting Thyroid Cytopathology: Risk of Malignancy in Pediatric Thyroid Nodules.

Introduction: Thyroid nodules are infrequent findings in children, though malignancy rates are higher in this population. The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) standardizes the reporting of thyroid fine needle aspiration (FNA) specimens and has become a global reference for assessing the risk of malignancy (ROM) of thyroid nodules. The 2023 update includes pediatric-specific risk predictions and management recommendations. Our study aimed to evaluate the ROM for each Bethesda (BT) category in our pediatric population and compare them with the 2023 TBSRTC update.

Methods: This retrospective cohort study studied pediatric patients who underwent FNA from 2008 to 2023 at our tertiary care center. ROM was assessed by comparing each Bethesda category with histology after thyroid surgery or with long-term follow-up data for non-surgical cases. Comparison among our observed ROM and the 2023 TBSRTC was done by assessing whether the mean ROM from the 2023 TBSRTC fell within the 95 % Confidence Intervals (CIs) of our cohort's ROM for each Bethesda category.

Results: 165 patients with thyroid nodules underwent FNA and Bethesda system classification. 55 patients were excluded due to incomplete follow-up. Thyroid surgery was required in 58 patients. All Bethesda I nodules were benign, while malignancy rates (ROM) were 10.5 % for Bethesda II, 42.8 % for Bethesda IV, 87.5 % for Bethesda V, and 100 % for Bethesda VI. The mean follow-up was 58,2 months (±41,4 SD, range 6-170 months). The comparison of the ROM in our cohort with the 2023 Bethesda pediatric population reveals notable consistency across all Bethesda categories.

Discussion: The ROM among patients with Bethesda II, IV, V, and VI was higher than reported in TBSRTC for adults and similar to those published in the 2023 TBSRTC for children. The development of updated pediatric-specific guidelines could have a significant impact on follow-up strategies and therapeutic algorithms.

Type Of Study: Prognosis Study.

Level Of Evidence: II (retrospective).