Evaluation of fine needle aspiration cytology of thyroid lesions by Bethesda system and its histopathological correlation

Abstract

: The Bethesda system of thyroid cytopathology (TBSRTC) established a standardized, category –based reporting system for thyroid fine needle aspiration cytology. The objective of this study was to analyse the thyroid cytology smears by TBSRTC, and to determine the distribution of diagnostic categories and subcategories, to analyse cytomophologic features and to correlate cytopathology with histopathology wherever surgery was done. In this study FNA of 248 patients of clinically palpable thyroid and deep-seated lesions were evaluated and categorised according to bethesda system of reporting thyroid cytopathology. 66 patients underwent surgical management in our hospital. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of FNA reported under bethesda system were obtained by comparing the cytological and histopathological diagnosis where ever possible. The distribution of various categories from 248 evaluated thyroid nodules is as follows: 2.82% ND/UNS, 83.87% Benign, 4.03% AUS/FLUS, 2.41% FN, 0.8% SFM and 6.04% malignant. Sensitivity, specificity, positive predictive value, negative predictive value were calculated. Simplicity, diagnostic accuracy and most of all cost effectiveness of FNA of thyroid has gained wide spread acceptance as first-line diagnostic test in the pre-operative evaluation of thyroid lesions. TBSRTC is an excellent reporting system for thyroid FNA. It also provides clear management guidelines to clinicians.