Comparative Study between Fine Needle Aspiration Cytology and Histopathologic Examination in Thyroid Enlargements - A Validation Study

ABSTRACT

Background:Swellings of thyroid are frequently encountered in surgical practice. Clinical evaluation helps in diagnosis but distinguishing early malignant lesions from benign goiters is difficult. Histopathological examination (HPE) is the only means by which precise diagnosis can be made. An alternative approach other than operative is called for since most swellings are benign. Fine needle aspiration cytology (FNAC) is a simple and safe procedure, carried out with minimum equipment and good patient compliance. This study aims at correlating the cytological diagnosis using Bethesda system for reporting thyroid cytopathology with the final histological diagnosis to evaluate the sensitivity, specificity, and positive predictive value of smears. Thereby, its role in the preoperative diagnosis of thyroid swellings is assessed in planning proper management. Materials and Methods: Consenting patients with a thyroid swelling undergoing both FNAC and surgery with HPE of the resected thyroid gland were included in the study and analyzed. Results and Conclusions: A total of 62 patients were included in our study and were graded into categories based on the Bethesda system of thyroid reporting. The histopathological results were compared with respect to the incidence of malignancy in each category classified as per Bethesda System of reporting Thyroid Cytopathology. The predictive values of FNAC in the present study were sensitivity 41.2%, specificity 96.97%, predictive value of a positive result 87.5%, and negative predictive value 74.4%. In the present study, an overall accuracy rate of 77.6% was obtained. We concluded that the Bethesda system of reporting thyroid cytopathology is effective; however, risk of malignancy is significantly high in Bethesda II category and therefore warrants further workup including ultrasound-guided FNAC of suspicious foci.