The role of cytology in diagnosing follicular pattern lesions of thyroid in a tertiary care hospital

Introduction: Fine needle aspiration cytology (FNAC) plays a vital role in diagnosing thyroid lesions. However, follicular patterned lesions need to be evaluated meticulously due to markedly overlapping cytomorphological features. Aim: The study aimed to evaluate the role of FNAC in follicular-patterned lesions of thyroid. Materials and Methods: A retrospective study of 50 cases in which thyroid FNAC showed follicular-patterned lesions along with histopathological correlation wherever available was done over a period of 3 years (November 2024-October 2021). Results: Out of 50 cases of follicular-patterned lesions, 44 cases were reported as adenomatous goiter (AG), 5 cases of follicular neoplasm (FN), and 1 case of follicular variant of papillary thyroid carcinoma (FVPTC) on FNAC. Out of total 30 cases available for histopathological correlation, 7 cases (23.3%) showed discordance and the possible causes for the discordance were analyzed. Conclusion: Diagnosing follicular-patterned lesions on FNAC is challenging and will remain a “gray zone” for all cytopathologists. A thorough examination of all cytological smears should be done for predominant follicular pattern along with cytomorphological and background details to differentiate follicular-patterned thyroid lesions in order to minimize false negative diagnosis on FNAC.