The correlation between fine needle aspiration diagnosis and postoperative histopathological results of pediatric thyroid nodules based on the Bethesda system
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Substernal Thyroid Biopsy Using Endobronchial Ultrasound-guided Transbronchial Needle Aspiration
Published on: November 10, 2014
Xue Bai1, Jingjing Xu1, Na Wei1
1Department of Pathology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
Background:
Pediatric thyroid nodules have higher malignancy rates than adult nodules, necessitating accurate diagnostic evaluation. This study evaluated the correlation between fine needle aspiration (FNA) results using the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) and postoperative histopathological findings in pediatric patients.
Methods:
This retrospective analysis included 696 pediatric patients who underwent ultrasound-guided FNA for thyroid nodules from 2017-2024. Cytological results were classified according to TBSRTC 2023 criteria and correlated with histopathological outcomes in 246 surgically resected cases. Molecular testing included BRAF V600E mutation analysis on FNA specimens in non-operated patients, while TERT promoter mutations, RAS mutations, and RET fusions were assessed in formalin-fixed paraffin-embedded surgical specimens. Risk of malignancy (ROM) was calculated using conservative (ROM-C) and histological (ROM-H) approaches. Diagnostic performance was assessed for definitive cytological categories (II, IV, V, and VI).
Results:
Among 246 operated patients, the overall ROM ranged from 32.76% (ROM-C) to 92.68% (ROM-H). ROM increased progressively across Bethesda categories: II (1.11%-27.27%), III (25.40%-66.67%), IV (22.22%-100%), V (74.70%-100%), and VI (82.39%-100%). Papillary thyroid carcinoma predominated (88.62%). BRAF V600E mutation was detected in 51.53% of histologically confirmed malignancies and 10.96% in FNA samples from patients who did not undergo surgery. RET gene fusions were identified in 5.24% of malignant cases, TERT promoter mutations in 0.44%, while no RAS mutations were detected. Within definitive cytological categories (II, IV, V, and VI), the Bethesda system demonstrated sensitivity of 98.58%, specificity of 100%, and accuracy of 98.63%.
Conclusion:
The Bethesda system provides high diagnostic accuracy for definitive cytological categories in pediatric thyroid nodules. Even indeterminate categories carry elevated malignancy risk, supporting careful surgical consideration and the value of BRAF V600E testing for preoperative risk stratification.
