Thyroiditis: a Clinico-cytomorphological Study with a Reference to the Ethnic Groups of Northeast Regions of India.

Definite clinico-cytological criterion is outlined for thyroid lesions. Fine needle aspiration cytology (FNAC) makes it easier to segregate cases of thyroiditis (Chronic lymphocytic thyroiditis/Hashimoto's thyroiditis-CLT/HT, and subacute thyroiditis-SAT) from other benign and malignant lesions of thyroid. The study was done for a period of 5½ years at a diagnostic centre in Guwahati. Patients underwent FNAC and smears were studied for cytomorphology. A correlation with clinical features and thyroid function, including antithyroid antibody estimation, was done, wherever possible. 792 thyroid lesions were encountered during the study, of which 213 (26.89 %) were cases of thyroiditis (70.43 % CLT/HT, 24.9 % SAT and 3.76 % having overlapping features of CLT/HT and SAT); 2 cases (0.9 %) of CLT showed suspicion of Non-Hodgkin's Lymphoma (NHL), which was confirmed on histopathology. 24 cases (11.26 %) belonged to different ethnic tribal groups of Northeast India. CLT/HT presented predominantly with diffuse thyroid enlargement, but 12 cases (8 % of CLT/HT cases) had nodular enlargement. Patients presented with predominantly hypothyroidism; however occasional hyperthyroid cases were also seen. SAT showed signs of inflammation and presented with hyperthyroidism. Overlap cases of CLT/HT and SAT showed combined clinico-cytomorphological features of both lesions. 37.5 % cases with overlapping features belonged to tribal communities. A rise in incidence of thyroiditis, particularly CLT/HT, was seen. Overlap features of CLT/HT and SAT was noticed in significant percentage. No bias was noticed amongst any specific tribal community. FNAC, coupled with clinico-serological study, helps to diagnose thyroiditis at early stage.