Correlation between ultrasonographic and cytologic features of thyroid nodules: a single-center cross-sectional study

Abstract

A thyroid nodule is managed according to the clinical context, ultrasound (US) findings, and fine needle aspiration (FNA) results. Most thyroid nodules are benign; however, nodule classification is crucial to avoid unnecessary thyroid surgery. We conducted this study to compare the findings of fine-needle aspiration cytology (FNAC) expressed using the Bethesda system with the features of thyroid US classified using the EU-TIRADS classification to assess the risk of malignancy. A descriptive and analytical study involving 99 patients with thyroid nodules followed up in the Department of Endocrinology-Diabetology and Nutrition. Data were collected from medical records and analyzed using SPSS software V21. FNA was performed on 121 nodules using the BETHESDA system. These nodules were classified as malignant, suspicious for follicular neoplasm, and suspicious for malignancy in 5.8%, 5%, and 1.7% of cases, respectively. As for the EU-TIRADS 2017 classification, 59.5% of benign nodules were classified as EU-TIRADS III, whereas 66.7% of malignant nodules were classified as EU-TIRADS V and significantly related to malignant prediction (P = 0.000). The size of nodules was significantly correlated to the risk of malignancy (P = 0.013). Seventy-five percent of nodules with central vascularity were malignant (P = 0.012). Irregularity of nodule contours was significantly associated with the risk of malignancy, as 30% of nodules with irregular contours were Bethesda VI (P = 0.003). Hypoechogenicity was found in 77.8% of malignant nodules (P = 0.004). Additionally, only 9.2% of the nodules were taller than wide, of which 37.5% were malignant (P = 0.012). For a safe management strategy, US-guided FNAC should be performed on each suspicious thyroid nodule, given the correlation between EU-TIRADS classification features and the risk of malignancy.

Keywords: ATA, American Thyroid Association; CI, Confidence Interval; EU-TIRADS; EU-TIRADS, European Thyroid Imaging Reporting and Data System; FNA, Fine Needle Aspiration; FNAC, Fine-Needle Aspiration Cytology; FT4, Tetraiodothyronine; OR, Odds Ratio; TBSRTC, The Bethesda System for Reporting Thyroid Cytopathology; TPOAb, Thyroid Peroxidase Antibody; TSH, Thyroid-Stimulating Hormone; TTW, Taller-Than-Wide; US, Ultrasound; fine-needle aspiration; malignancy; thyroid nodule; ultrasound.