Autoimmune thyroiditis – Correlation of clinico-radiological presentation, thyroid profile and cytomorphological spectrum

Background: Thyroiditis is the second most common thyroid lesion next to endemic goitre diagnosed on FNA in iodine (I2) deficient areas. Although FNAC is the gold standard for diagnosis of thyroiditis, accurate diagnosis of a thyroid lesion at FNAC requires not just an in depth study of the cytomorphology but also a thorough clinico- radiological and serologic correlation. Aim: To study and correlate the clinical, radiologic, serologic and cytomorphological spectrum of autoimmune thyroiditis. Materials and methods: Retrospective study involving 150 cases was conducted. Clinical history (age, sex, symptoms with their duration and other signs, other significant medical/surgical history), TFT, were noted from the medical record available with the patient and also from Endocrinology department records. Results: Incidence of autoimmune thyroiditis was found to be 13.4%. Majority of the patients were females (96.7%), 53.3% of cases were seen in the age group of 21-40 years. 80.6% patients had a diffusely enlarged thyroid gland clinically. 92.7% patients showed grade I/II goitre. USG also showed a diffuse enlargement in 85.3% cases. Of the 150 patients with autoimmune thyroiditis, 110(73.3%) patients were euthyroid while 32 (21.3%) patients were hypothyroid at the time of FNAC. Only 8(5.3%) patients showed evidence of hyperthyroidism. 8% patients showed subclinical hypothyroidism. Prevalence of euthyroid autoimmune thyroiditis appeared high in our study. Among the cytomorphological features, presence of lymphocytes was consistently seen in all cases of chronic lymphocytic thyroiditis /mixed thyroiditis. Hurthle cells were seen in 68.6%, eosinophils were seen in 16.6%, giant cells and granulomas were noted in 29.3% and 8.6% cases respectively. L:E ratio was high in 101 (67.3%) cases ranging from 2:1 to 10. TFC destruction and grade III thyroiditis showed a significant association. Conclusion: Autoimmune thyroiditis was seen more commonly in females. Majority cases were seen in age group of 21-40 years of age. Lymphocytes, germinal centre cells, thyroid follicular destruction and Hurthle cells form important cytological features, while giant cells, eosinophils, granulomas were other cytomorphologic features in the diagnosis of autoimmune thyroiditis. Clinically and radiologically most of patients showed diffuse enlargement of thyroid gland. Majority of patients in our study were euthyroid at time of presentation. Prevalence of euthyroid autoimmune thyroiditis appeared high in our study. TFC destruction and grade III thyroiditis showed a significant association.