Background: Bethesda system of thyroid lesion is the six-tired diagnostic classification based on a probabilistic approach in increasing the specificity and sensitivity of FNAC thyroid lesions. Its capacity to facilitate better cytologic -histologic correlation and role of each diagnostic category to conveys specific risks of malignancy. Methods: The present retrospective study of Bethesda system of cytopathology of thyroid lesion was carried in 100 cases in the department of Pathology, Narayana Medical College & Hospital, Nellore, Andhra Pradesh, India, during the period of January 2016 to December 2016. Cytological smears was fixed in ethylalcohol and then stained with Haematoxylin and Eosin staining technique. Results: In our study the lesion wise distribution after The Bethesda System of Reporting Thyroid Cytopathology (TBSRTC) was benign 77.5%, Atypia of undetermined significance 3.5%, with Follicular Neoplasm at 6%, suspicious for malignancy at 2% and malignant at 11%. The sensitivity and specificity after TBSRTC were 88.13% and 100% respectively with a diagnostic accuracy of 98.55%. On estimation of risk for malignancy in each category it showed 1.95% for benign lesions, 33.33% for Follicular Neoplasm category, suspicious for malignancy had 50% risk and 100% risk for malignancy category. Conclusion: The malignancy potential of each category of Bethesda system gives clinician a clear idea regarding its treatment strategy and TBSRTC has a histopathological correlation as good as any system of reporting.

Keywords: Thyroid Cytopathology; Bethesda System.