Abstract
This study aimed to determine the relationship between the presence of Hashimoto's thyroiditis (HT) and malignancy rates with prognostic factors in thyroid nodules diagnosed as Bethesda category III, and to examine the effect of HT on diagnostic value of fine-needle aspiration biopsy (FNAB). Demographic information, preoperative examination, and final pathological evaluation of patients with Bethesda category III (AUS-FLUS) nodules who had been operated on in our department over the last 6 years were analyzed. Statistical analyses were performed using the Student's t-test, Mann-Whitney U test and χ(2)-test and logistic regression analysis using SPSS version 22 software. The malignancy rate on final pathology of 159 patients was 24.5%. Malignancy rates were found to be higher in patients with HT coexistence (30.7% vs. 21.5%, p=0.20). Poor prognostic factors such as multifocality, number of metastatic lymph nodes (p=0.04), and extrathyroidal extension were more common in patients with cancer in the pathology specimen who were in the non-HT group. It cannot be said that HT decreases diagnostic value of FNAB in lesions diagnosed with AUS-FLUS. The lower incidence of poor prognostic factors in the HT group may be attributed to cytotoxic cell dominance in tumor immunity.