Role of Multiparameter Analysis of AgNORs in FNA Smears of Thyroid Swellings in Differentiating Benign and Malignant Lesions

Background. The aim of this study is to assess the role of multiparameter analysis of silver (Ag)-stained nucleolar organizer regions (AgNORs) technique on aspiration smears of thyroid swellings to distinguish between benign and malignant lesions. Materials and Methods. Aspiration smears from 166 cases of thyroid swellings were examined. Diagnosis was confirmed by histology in 61 cases. AgNOR staining was done on FNA smears according to silver-staining protocol proposed by the International Committee for AgNOR quantification. Multiparameter analysis of AgNORs such as mAgNOR, pAgNOR, and AgNOR size grade was done on 50-100 cells under oil immersion lens. Results. AgNOR parameter of benign and malignant thyroid lesions was compared and was found to be statistically significant. Out of 157 satisfactory AgNOR stained cases, 148 (94.3%) were benign lesions and 9 (5.7%) cases were malignant lesions. In AgNOR analysis, sensitivity was found to be 83.33%, specificity 100%, PPV 100%, NPV 98.21%, and accuracy was 98.36%. Conclusions. AgNOR analysis in the FNA smears is a simple, sensitive, and cost-effective method for differentiating benign from malignant thyroid swellings.