Evaluation of Cyto-Morphological Profile of Thyroid Swellings Using Bethesda System for Reporting and its Correlation with Biochemical Parameters in Cases of Autoimmune Thyroiditis: A Sub-Himalayan Tertiary Care Experience

Abstract

Background: Thyroid disorders are among the commonest endocrine disorders worldwide, including India. FNAC (fine needle aspiration cytology) is used for thyroid swelling as the initial diagnostic test due to its superior diagnostic reliability and costeffectiveness. Thyroid antibody levels and thyroid function test are among the many other initial tests available for thyroid lesions.Objective: To study the cytomorphological profile of thyroid swelling using the Bethesda system for reporting thyroid cytopathology in a sub-Himalayan tertiary care centre, and assess correlation of biochemical parameters in cytologically diagnosed cases of autoimmune thryoiditis. Materials and Methods:In this retrospective study, departmental records of FNAC performed for thyroid swelling between March 2018 and February 2021 were retrieved and analysed. The Bethesda system was used for reporting of cytology. Biochemical parameters such as antithyroid peroxidase antibody (Anti-TPO) and thyroid stimulating hormone (TSH) of autoimmune thyroiditis were assessed to find out their association with the cytopathology.Results: A total of 303 FNAC of palpable thyroid swelling were included in the present study. 9 (2.97%) cases were nondiagnostic-Bethesda category I, 256 (84.49%) were diagnosed as benign-category II, 4 (1.32%) atypia of undetermined significance or follicular lesion of undetermined significance (AUS/AFLUS)-category III, 10 (3.30%) as follicular neoplasm or suspicious for follicular neoplasm (FN/SFN)-category IV, 2 (0.66%) suspicious for malignancy (SM)-category V and 22 were malignant-category VI. Among the benign cases (category II), the final diagnosis was colloid goitre in 143 (47.19%) and autoimmune thyroiditis in 102 (33.66%). Out of 102 autoimmune thyroiditis cases, biochemical reports (Anti-TPO and TSH) were available in 85 patients. Anti-TPO was raised in 74 out of 85 cases (87.06%). Sixty three of 85 (74.11%) cases were euthyroid, 18 (21.18%) hypothyroid and 04 (4.71%) hyperthyroid. In category VI, papillary carcinoma and anaplastic carcinoma was seen in 20 (6.60%) and 2 (0.66%) cases respectively. Conclusion:Colloid goitre followed by autoimmune thyroiditis, were the most common lesions on evaluating thyroid swelling.Relatively autoimmune thyroiditis was more prevalent in our region.