The Diagnostic Landscape of Thyroid Cytopathology: A Cross-Sectional Analysis of the 2023 Bethesda System and its Histopathological Correlation

Background: Fine-needle aspiration cytology (FNAC) is a widely used, cost-effective diagnostic method for evaluating thyroid nodules and differentiating benign from malignant lesions. The 2023 Third Edition of the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) introduced updated terminology and refined risk-of-malignancy estimates to enhance diagnostic accuracy and improve clinical decision-making.

Methods: This cross-sectional observational study was conducted in the Department of Pathology, Agartala Government Medical College and GBP Hospital, Tripura, from December 2022 to November 2025. A total of 281 thyroid FNAC cases were analysed and categorised according to the 2023 Bethesda system. Cytological diagnoses were correlated with histopathological findings in 183 cases that underwent surgical resection. For statistical analysis, Bethesda Categories V and VI were considered positive for malignancy, while Category II was considered negative. Diagnostic parameters, including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall diagnostic accuracy, were calculated.

Results: The study population was female predominant (82.9%), with a male-to-female ratio of 1:4.8. The majority of cases occurred in the 21–40-year age group. Category II (benign) constituted the largest proportion of cases (74.7%). Among benign lesions, lymphocytic thyroiditis was the most common, whereas papillary thyroid carcinoma was the predominant malignant lesion. Cytology–histology correlation demonstrated a sensitivity of 90%, specificity of 98.7%, PPV of 93.1%, NPV of 98.1%, and an overall diagnostic accuracy of 97.3%.

Conclusion: The 2023 Bethesda system shows excellent diagnostic performance and remains a reliable preoperative tool for evaluating thyroid nodules in tertiary care settings.