A Study of Fine Needle Aspiration Cytology of Thyroid Lesions with Histopathological Correlation

Abstract

Background: Fine Needle Aspiration Cytology (FNAC) is important for pre-operative and pre-treatment diagnosis of benign and malignant thyroid lesions, thus decreasing the incidence of unwanted surgeries. Objectives: The present study aims to classify various cytomorphological lesions of the thyroid according to The Bethesda System for Reporting of Thyroid Cytopathology (TBSRTC) and correlate these with histopathology wherever possible. Material & Methods: A prospective study was conducted in a tertiary care centre of Western Uttar Pradesh to evaluate the diagnostic accuracy of FNAC in lesions of thyroid during a 2 year period. The cytological findings were classified according to the recent TBSRTC. Cyto-histopathological correlation was done in all the cases subjected to surgery. Results: Out of total 281 cases studied, 247(87.90%) were benign, 4(1.42%) were neoplastic, 5(1.78%) were suspicious for malignancy, 7(2.49%) were suspicious for a follicular neoplasm, 11(3.91%) were Atypia of undetermined significance and 7(2.49%) were inadequate. Cyto-histopathologic correlation of 134 cases was done. Sensitivity, specificity and diagnostic accuracy of the study for malignant lesions were 96.7%, 100 % and 97.0% respectively. Conclusions: FNAC is a safe, simple, highly accurate, economical and universally accepted modality for evaluation of thyroid lesions especially in developing countries such as India. FNAC helps in avoiding unwanted surgeries in patients diagnosed to have a benign pathology based on cytology. Those that are grouped in the suspicious or indeterminate categoryon cytology include lesions of uncertainty that are finally confirmed on histopathology. Keywords: FNAC, Thyroid, Histopathology correlation, Diagnostic Accuracy, Sensitivity, Specificity.