Abstract
BACKGROUND: Thyroid nodules are a common pathology worldwide. Fine needle aspiration biopsy (FNAB) is an important diagnostic method for the investigation of malignancy in thyroid nodules. However, according to the Bethesda System used to classify the results, patients with atypia of undetermined significance/follicular lesion of undetermined significance (AUS / FLUS) may not be classified as benign or malignant. Therefore, it may be necessary to determine some clinical risk factors to apply the best treatment in these patients. AIM: To determine the factors that increase the risk of malignancy in this patient group. METHODS: A retrospective study including 138 patients with an FNAB categorized as AUS/FLUS and operated between June 2015-September 2018. Demographical, Laboratory (TSH) and Ultrasound variables (number, size and characteristics of nodules) of the patients were compared among postoperative histopathological results. RESULTS: Hypo-echoic structure, microcalcification and irregular margin of the nodules were detected to be associated with malignancy in patients with FNAB results of AUS/FLUS (p <0.001). CONCLUSION: We suggest that surgical treatment should be considered if the patients have nodules with the hypo-echoic structure, microcalcification and irregular margin with an FNAB histopathological result of AUS / FLUS.