Malignancy rate of thyroid nodules which defined as follicular lesion of undetermined significance in thyroid cytopathology
N. Cuhaci1, R. Ucler1, D. Arpaci1, S. Akbaba1, S. Yalcin2, G. Kiyak1, G. Guler2, R. Ersoy2 & B. Cakir2
Objective: In the Bethesda classification (BC), which is used in cytopathologic evaluation of thyroid nodules, follicular lesion of undetermined significance (FLUS) does not involve sufficient cellular atypia for follicular neoplasia or malignancy, while it doesnt comprise the cytologic benign criteria. Therefore, there is no consensus for those nodules to follow-up and therapeutic approaches. In this study, we aimed to determine the ultrasonographic features and histopathologic results of the thyroid nodules which are defined FLUS in BC.
Methods: We evaluated 64 nodules of 62 patients, who have nodular or multinodular goiter and had diagnosed FLUS at least in one nodule with fine-needle aspiration (FNA). Operation indication was decided upon to the nodule size, suspected ultrasonographic feature (border irregularity, solid, hypoechoic nodule, presence of microcalcification), high elastosonographic score and strain index and family history of thyroid cancer.
Results: ###87.5% of patients were female, 12.5% were male. Mean age was 46.5±12.6 years. 51.6% of nodules were located in the right lobe, 45.3% in the left and 3.1% in the isthmus. According to the echogenite and component 43.8% of nodules were hypoechoic, and 57.8% were solid. Microcalcification, peripheral vascularization and border irregularity positivity was respectively 25.5%, 17.2% and 59.4% of nodules. After operation, 68.7% of nodules were benign (n=44), 31.3% (n=20) were malign. 85% of malign nodules were papiller thyroid carcinoma, 15% were follicular carcinoma.
Conclusion: In our study, we found malignancy rate 31.3% in FLUS compared to the 520% reported by different studies. Therefore, we think that, in the diagnostic and therapeutic approach of the FLUS nodules that challenge the clinician, this high ratio of malignancy must be kept in mind.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector