Comparison between Fine Needle Aspiration Cytology of Thyroid Nodules and Histology after Surgical Excision

Abstract

Background: Thyroid nodules are an extremely common disorder. Fine Needle Aspiration (FNA) is the gold standard procedure for thyroid nodules diagnosis and management; it helps clinicians to make a proper therapeutic decision and minimizes the need for unnecessary surgery. Objective: To assess thyroid FNA sensitivity, specificity, accuracy, Positive Predictive Value (PPV), and Negative Predictive Value (NPV) in Al-Assad University Hospital using the Bethesda system for reporting thyroid cytology. Methods: We prospectively followed thyroid FNAs, then the histological results were followed after performing surgery. FNA was performed by endocrinologists in al-Assad and al-Mouwassat university hospitals, and the cytological study for all samples was performed in pathology department at al-Assad university hospital. All available data were analyzed with SPSS version 23 statistical program. Results: A total of 381 nodules from 324 patients, 281 women (86.7%), aged between 13-80 years (46.1 ± 13.01) had FNA. There were 26(6.8%), 216(56.7%), 52(13.6%), 44(11.5%), 30(7.9%), and 13(3.4%) nodules in categories unsatisfactory, benign, Atypia of undetermined significance/ Follicular lesion of undetermined significance AUS/FLUS, Follicular neoplasm/Suspicious for Follicular Neoplasm (FN)/(SFN) Suspicious for Malignancy, and malignant, respectively. Histology was obtained for 172 nodules, sensitivity, specificity, PPV, NPV, and accuracy were 85%, 79.35%, 47.22%, 96.05% and 80.36%, respectively. Malignancy rate in unsatisfactory, AUS/FLUS, and FN/SFN cytology was 0%, 9.1%, and 6.5%, respectively. Conclusion: Specificity was slightly lower than anticipated based on global data and so did the PPV that may be due to the trend of overestimating cellular irregularity, however fine needle aspiration biopsy remains an accurate procedure in excluding malignancy due to its high sensitivity and NPV.