Evaluation of Thyroid Fine Needle Aspiration Cytology (FNAC) with Histopathological Correlation: A Cross-Sectional Study

Abstract

Background: Thyroid nodules are prevalent, with 5–15% exhibiting malignancy, necessitating precise diagnostic evaluation. Objectives: To determine the sensitivity, specificity, and diagnostic accuracy of FNAC in thyroid lesions by comparing cytological findings with histopathological examination results. Methods: This cross-sectional study included 132 patients with thyroid nodules who underwent FNAC followed by histopathological evaluation in private clinics in Dhaka. FNAC was performed using a 22–25-gauge needle, with cytological classification based on The Bethesda System. Findings were compared with histopathological diagnosis. Sensitivity, specificity, and kappa statistics were analyzed using SPSS. Ethical approval was obtained, and informed consent was secured to maintain confidentiality. Statistical significance was set at p<0.05. Results: Among the 132 participants, females constituted 75.8%. FNAC classified 56.8% of cases as benign and 11.4% as malignant. Histopathological examination confirmed benign nodular goiter as the most prevalent diagnosis (54.5%), followed by papillary thyroid carcinoma (22.7%). FNAC demonstrated high sensitivity (85.7%) and specificity (92.1%). A strong concordance between FNAC and histopathology was observed (κ=0.82). Advanced age, nodule size >2 cm, and FNAC suspicion were significant predictors of malignancy. Conclusion: This study underscores the high diagnostic accuracy of FNAC in evaluating thyroid lesions, demonstrating strong concordance with histopathological findings.