Cytomorphologic spectrum of Hashimoto's thyroiditis and its clinical correlation: A retrospective study of 52 patients

BACKGROUND: Hashimoto's thyroiditis (HT) is an autoimmune disease and it is more prevalent in Asians. The incidence of HT seems to be increasing in the recent times. It is one of the most common cause of hypothyroidism. The purpose of this study is to review the cytomorphologic spectrum of HT and correlate it with clinical findings including thyroid function and antibody profile. MATERIALS AND METHODS: We retrospectively analyzed the fine-needle aspiration (FNA) features of 52 HT patients. Based on cytomorphologic features patients were categorized into three groups. Clinical findings including thyroid function and thyroid peroxidase (TPO) antibody profile were correlated with cytomorphologic features in all three groups. RESULTS: Majority of the patients were females and in 2(nd), 3(rd) and 4(th) decades. Diffuse goiter and thyroid hypofunction were the common findings. Significant number of patients had thyroid hyperfunction. Increased lymphocytes on the background and lymphocytic infiltration of thyroid follicular cell clusters in cytology smears were diagnostic of HT. The 32 patients showed elevated titers of TPO antibodies. In the early stages and mild form of the disease, results of thyroid function and anti TPO antibodies are quite variable. CONCLUSIONS: HT is a disease of young and middle age and mostly occur in females. Clinical findings alone may not be adequate for definitive diagnosis. FNA is the gold standard for diagnosis. In the presence of abundant colloid, follicular hyperplasia or co-existing neoplasm, careful interpretation of cytology smears should be done. Aspiration from more than one site minimizes the diagnostic pitfalls.