Significance of Crushed Fragments and Eosinophils in Cytological Diagnosis of Hashimoto's Thyroiditis.

Introduction Hashimoto's thyroiditis (HT) is a chronic autoimmune inflammatory disorder of the thyroid gland with a prevalence of 1%-4%. The incidence of HT seems to be increasing in recent times. If serological parameters are used as sole criteria for diagnosis, cases of HT get missed or over-diagnosed. There are established cytological features of HT but that could, at times, be seen in other thyroid disorders, making cytological diagnosis difficult. The present study was undertaken to find out the significance of crushed fragments and eosinophils along with the well-known cytological features in the diagnosis of HT. Methods This study was carried out over a period of two years and a total of 114 patients were registered for the study; 48 patients were HT cases. The control group comprised of 66 non-thyroiditis patients. Fine-needle aspiration cytology (FNAC) was performed on all patients with palpable thyroid swelling to compare cytological features of thyroiditis (study group) with aspirates of non-thyroiditis lesions (controls). Results The background lymphocytes were found to be present in all cases of the study group but in variable numbers. The lymphocytes infiltrating the follicular epithelial cells were seen in most (93.75%) of the study cases. The presence of Hurthle cells was significantly higher (83%) in the study group as compared to the control group (4.5%). The presence of crushed cells morphology (crushed fragments) were seen in 40 (83.33%) of these 48 HT cases while none in the control group showed this feature. The presence of eosinophilic infiltration shows a statistically significant association with FNA diagnosis of HT patients (P<0.05). Conclusion The crushed fragments, if visible at low power, gives a diagnostic clue for looking up for other features of HT. Also, the crushed fragments and eosinophils could avoid the false negative and misdiagnosis of neoplasm in paucicellular and highly cellular smear respectively.