Fine-needle aspiration biopsy with subsequent liquid-based cytology in the diagnosis of nodular goiter: analysis of cytological and histological results

We have analyzed the results of 885 fine-needle aspiration biopsies (FNABs) performed in Medgard LLC (Samara, Russian Federation) in 2019. The specimens obtained by FNAB were evaluated using liquid-based cytology (LBC) and classified according to the Bethesda System for Reporting Thyroid Cytopathology, 2017 (TBSRTC, 2017). Only 2.5% of specimens were found to be non-diagnostic (TBSRTC category I); malignant tumors were detected in 7.8% of cases (TBSRTC category VI); 67.9% of specimens were classified as benign (TBSRTC category II); 21.4% of specimens had atypia of undetermined significance, including follicular tumor/suspected follicular tumor (TBSRTC category IV). To evaluate the risk of malignancy in case of undetermined LBC results (TBSRTC category IV), we compared and analyzed the results of cytological and subsequent histological examination in 74 patients who had undergone surgery. The risk of malignancy in the group analyzed was 36%, which is comparable to the risk of malignancy reported in the Bethesda System for Reporting Thyroid Cytopathology, 2017 (TBSRTC, 2017).