Performance of the 2023 Bethesda System for Reporting Thyroid Cytopathology in a pediatric cohort: a single-center...

Pediatric thyroid nodules are uncommon but have higher malignancy risk than adult nodules. The 2023 TBSRTC updated ROM estimates and expanded pediatric guidance, but data remain limited.

We reviewed 63 thyroid FNAs from patients aged 21 years or younger at a tertiary center (January 2023-October 2025). Cases were classified according to the 2023 TBSRTC. Observed ROM was calculated in resected nodules with exact 95% CIs. Bethesda III nodules were subclassified as AUS with nuclear atypia or AUS-other.

Diagnoses were Bethesda I in 5/63 (7.9%), Bethesda II in 32/63 (50.8%), Bethesda III in 3/63 (4.8%), Bethesda IV in 10/63 (15.9%), Bethesda V in 13/63 (20.6%), and Bethesda VI in 0/63 (0%). Histologic follow-up was available for 36 nodules. Observed ROM among resected nodules was 0/1 (0.0%) for Bethesda I, 1/11 (9.1%) for Bethesda II, 2/3 (66.7%) for Bethesda III, 4/8 (50.0%) for Bethesda IV, and 12/13 (92.3%) for Bethesda V. The two malignant Bethesda III cases were AUS with nuclear atypia; the AUS-other case was benign. Overall malignant yield was 19/36 (52.8%).

The 2023 TBSRTC was applicable in this pediatric cohort. Bethesda II, IV, and V ROM estimates were broadly consistent with published pediatric data, whereas Bethesda III was imprecise because only three nodules were resected. Larger multicenter studies with standardized follow-up and explicit AUS subclassification are needed.