A study of fine needle aspiration cytology findings with thyroid function test, anti-thyroid antibody, and clinical pathological parameters in cases of chronic lymphocytic thyroiditis

Abstract

: Chronic lymphocytic thyroiditis is autoimmune thyroiditis; it is considered as second most common thyroid disorder diagnosed on FNAC following colloid goitre. FNAC is a reliable and efficient method for diagnosing these thyroid lesions. Chronic Lymphocytic thyroiditis frequently affects women, primarily compared to men and is commonly found with hypothyroidism, euthyroidism or every so often with hyperthyroidism. The incidence rate of Hashimoto’s thyroiditis is 1–4%, with an occurrence of 30–60/100000 population per year. Autoimmune thyroiditis can be categorised on the cytomorphological features of FNAC. To compare FNAC cytological findings with TFT in Chronic lymphocytic thyroiditis. One hundred ten patients with thyroid swellings were presented for FNAC examination, serology of TFT and Anti TPO antibodies and Ultrasonography during 2020–2021. In addition, fine needle aspiration cytology was performed using non-aspiration or aspiration techniques. TFT and Anti- TPO antibodies were performed on Avion CLX 120 auto analyser based on the Chemiluminescence method. Out of 110 cases of midline neck swelling presented in our department, Autoimmune Thyroiditis was observed in 43 cases. The most affected age group of lymphocytic thyroiditis was 21–30 years, with the male: female ratio being 1:3. Most of the patients presented with diffuse swelling and few presented with nodular swelling. The Grading of the lymphocytic thyroiditis was done by the criteria used by Bhatia et al Anti-TPO antibody was elevated in 19 cases (26.2%), and TSH was elevated in 28 cases (40.81%). These cases were diagnosed as autoimmune thyroiditis on cytology, clinically and also correlating with radiological findings. Grade 3 lymphoid infiltrate was seen in 53.33% (16/30) cases, and Grade 2, lymphoid infiltrate was seen in eight cases (62.50%). Grade 1 lymphoid infiltrate was seen in five cases (11.63%). Among 43 cases, 28 cases (65.12%) show hypothyroidism, 7 cases (16.28%) show hyper, and 8 cases (18.60%) show Euthyroidism. Among these 43 cases, 26 cases showed diffuse thyroid swelling on ultrasonography, and 7 cases showed solitary nodule. Grade 3 lymphocytic infiltration statistically correlates with anti-TPO and TSH in conjunction with ultrasonography findings of diffuse enlargement of the thyroid gland. The presence of Hurthle cell change, giant cells, anisonucleosus, and granulomas do not find to be any statistical correlation with lymphocytic thyroiditis as these cases are primarily corresponding to Grade 1 and Grade 2. Through this study, we conclude that FNAC remains the gold standard method despite having different diagnostic modalities accessible for diagnosing thyroid lesions. Grading of FNAC Smears depends on lymphocytic infiltration of the thyroid follicles, along with positivity for antithyroid antibodies (anti-TPO antibody) and TSH. These findings are firmly associated with Chronic Lymphocytic Thyroiditis.