Statistical significance of AgNOR counts in FNAC smears and corresponding histopathological sections

The object of the present study was to determine the statistical significance of AgNOR counts in fine needle aspiration cytology (FNAC) smears and corresponding paraffin sections by using an one step silver colloidal staining method. Ninety five cases (31 benign and 64 malignant) were taken and a correlation between smears and sections was studied by two different observers. The total number of mean (SD) AgNOR counts was significantly higher in FNAC smears in benign (3.081 +/- .753) and malignant (7.101 +/- 1.544) neoplasms in comparison to paraffin sections in the same group of cases. FNAC smears had a cut off point 4 with proliferation index 1% in benign tumors and 97.5% in malignant tumors. Sections had an overlapping of AgNOR counts (5-7) with proliferation index 3.8 and 82% for benign and malignant groups respectively. The difference in the coefficient of variations was 3% in benign group and 2% in malignant group in FNAC smears while sections had 6 and 8% difference in the coefficient of variations. Smears present a superior staining and accurate number of AgNOR dots in nucleus as compared to paraffin sections. Therefore the results suggest that AgNOR technique can be successfully used in FNAC smears in comparison to paraffin sections to differentiate benign and malignant tumors in routine laboratory diagnosis.