Thyroid cytopathology reporting by Bethesda system

Background: Thyroid nodules are common in the general population, with a clinical prevalence between 5.3% to 6.4% for women and between 0.8% to 1.6% for men in normally “iodine countries”. Thyroid FNAC represents a simple, fast, reliable and minimally invasive technique to explore nodules. The Bethesda System for reporting thyroid cytology is standardized, reproducible and clinically significant system. Aim: The present study was aimed at evaluation of FNAC smears of thyroid swelling as per guidelines of ‘The Bethesda System of Reporting Thyroid Cytopathology’, its categorization into six different categories and its correlation with histopathology wherever possible. Methods: The prospective observational study was conducted at tertiary care center in which 120 cases of thyromegaly were subjected to FNAC. Smears were prepared by conventional method and stained with H&E and Giemsa stain. Thorough microscopic examination of all smears was done. Cytological features were evaluated and reporting was done by ‘The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC)’ to categorize the smears into six different categories. The cytohistopathological co-relation was done wherever possible. Result: Present study showed female predominance. The mean age of presentation of thyromegaly was 38.18 years. Out of the 120 FNACs 93.33 % of cases were benign. However 4.16% of cases and 2.5% of cases were Category I (ND/UNS) and Category IV (FN/SFN) respectively. Cytohistological correlation was possible in 20.83% of cases. Conclusion: Reporting by Bethesda System is an accurate and precise tool for the diagnosis of thyroid lesion on cytology, which triages the patients for clinical management. This can be used as a primary modality in the evaluation of thyroid lesions as the accuracy rate is fairly good.