The Role of Fine Needle Aspiration Biopsy with Bethesda System in The Evaluation of Thyroid Nodules

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Anadolu Kliniği Tıp Bilimleri Dergisi, vol.26, no.1, pp.23-30, 2021 (Peer-Reviewed Journal) identifier



Aim: In this study, the role of fine needle aspiration biopsy (FNAB) evaluated with the Bethesda System in the diagnosis of thyroid nodules was investigated.

Materials and Methods: Total 2284 FNAB materials of 1846 patients were performed in the Pathology Department of Kutahya Health Sciences University, Evliya Celebi Traning and Research Hospital between 2016 and 2019 and reported according to the Bethesda category. Among these cases, diagnostic sensitivity, specificity, accuracy, positive and negative predictive values of FNAB were calculated by making cytohistopathologica comparison in 328 cases who underwent total thyroidectomy.

Results: In the study, 1538 of the 1846 patients included were female (83.31%) and 308 (16.68%) were male. The average age was 49.92 years (Age range 19-87). The final cytological diagnoses of 2284 FNABs were as follows: 287 (12.57%) nondiagnostic or unsatisfactory, 1517 (66.42%) benign cytology, 316 (13.83%) atypia of undetermined significance/follicular lesion of undetermined significance, 63 (2.75%) follicular neoplasm or suspicious for a follicular neoplasm, 59 (2.59%) suspicious for malignancy and 42 (1.84%) malignant cytology. Histologically, 245 (74.70%) of the 328 cases were benign, while 83 (25.30%) were malignant. The number of true negative cases was 216 (65.85%), the number of true positive cases was 62 (19.90%), the number of false positive cases was 29 (8.84%) and the number of false negative cases was 21 (6.40%). In this case, diagnostic sensitivity, specificity, accuracy rates, positive and negative predictive values were 74.7%, 88.16%, 84.76%, 68.13% and 91.14%, respectively.

Conclusion: In our study, it was observed that the sensitivity, specificity, accuracy rates, positive and negative predictive values of thyroid FNABs were compatible with the literature. We think that as the experience of the clinician and cytopathologist increases, false negative and positive results will decrease and at the same time, the confidence in thyroid FNABs will increase even more with the participation of some recent molecular methods (BRAF and RET/PTC, AX8/PPARG and RAS) applied to FNABs.