Accuracy of fine needle aspiration cytology with histopathology of thyroid lesions - 1.5 years study at Government ENT hospital, Hyderabad, Telangana

Background: Swellings of thyroid gland are common in most parts of the world, including countries like India where iodine deficiency is endemic. Its prevalence ranges from 4% to 10% in the general adult population and from 0.2% to 1.2% in children, affecting females more commonly than males. Aim and objective: To evaluate diagnostic accuracy of Fine needle aspiration cytology of thyroid lesions, to categorize thyroid lesions as per the Bethesda system, to correlate cytomorphology with histopathology, to determine the accuracy of FNAC in terms of sensitivity, specificity, positive predictive value and negative predictive value in comparison with histopathology in the diagnosis of a thyroid lesions. Materials and methods: It was a retrospective study undertaken over a period of one and half years from October 2016 to March 2017 in the Department of Pathology, Government ENT Hospital, Hyderabad. FNAC was performed with 26 gauge needle; smears were fixed in ether-95% alcohol solution and stained with Haematoxylin and Eosin stain. Different types of excised thyroid specimens received were subjected to routine processing, cutting, staining and histopathological features were analysed. Results: The sensitivity, specificity, positive predictive value, and negative predictive value of aspiration cytology in detecting all the benign and malignant lesions of thyroid were 67.4%, 99.2%, 93.9%, and 94.2% respectively. The diagnostic accuracy of detecting thyroid lesions by FNAC was 94.1%. Conclusion: Fine needle aspiration cytology is a minimally invasive, simple, reliable, safe and cost effective gold standard cytology technique with minimal discomfort and complications to the patient. FNAC avoids unnecessary thyroidectomies for benign thyroid pathologies.