Korean Thyroid Imaging Reporting and Data System features of follicular thyroid adenoma and carcinoma: a single-center study

Abstract

PurposeThis study aimed to assess the diagnostic efficacy of Korean Thyroid Imaging Reporting and Data System (K-TIRADS) features for distinguishing follicular thyroid adenoma (FTA) from follicular thyroid carcinoma (FTC).MethodsFrom January 2013 to July 2016, 46 follicular neoplasms in 45 patients who underwent preoperative thyroid ultrasonography (US) and thyroid surgery were included. The US features of each thyroid nodule were retrospectively evaluated by a single radiologist using a picture archiving and communication system. The diagnostic indices of K-TIRADS for follicular neoplasms were calculated according to whether K-TIRADS category 4 lesions were excluded or classified as benign or malignant.ResultsOf the 46 follicular neoplasms (mean size, 3.1±1.6 cm), 37 were FTAs (mean size, 3.1±1.7 cm) and nine were FTCs (mean size, 3.0±1.5 cm). A statistically significant difference was found between FTAs and FTCs regarding the margin (P=0.035), while no significant differences were observed in the composition, echogenicity, shape, orientation, calcification, or vascularity of the lesions (P<0.05). The FTAs belonged to K-TIRADS categories 3 (n=22) and 4 (n=15), while the FTCs belonged to K-TIRADS categories 3 (n=4), 4 (n=4), and 5 (n=1). However, there was no statistically significant difference in the distribution of K-TIRADS categories between FTAs and FTCs (P=0.184).ConclusionK-TIRADS features were not helpful for distinguishing FTA from FTC, although follicular neoplasms showed a high prevalence of K-TIRADS categories 3 and 4.

Dedicated neck 18F‐FDG PET/CT: An additional tool for risk assessment in thyroid nodules at ultrasound intermediate risk

“…The worldwide use of US assessment of thyroid nodules has significantly improved the management of thyroid patients, and current guidelines are gaining consensus for clinical practice. On the other hand, the increasing diffusion of 18 F‐FDG PET/CT led to a significantly improved management of oncological patients also in the thyroid field.…”

“…Whether 18 F‐FDG PET/CT can hold a role in the (re‐)assessment of thyroid nodules and finally in the diagnosis of thyroid cancer is still unknown. The present study was undertaken to evaluate if 18 F‐FDG PET/CT could help to stratify the risk of malignancy of thyroid nodules at intermediate risk at US given the expected low‐moderate cancer prevalence in this class …”

“…Nevertheless, some limitations of US, such as low reproducibility and operator‐depending performance, may reduce its value. Consequently, in the last years several US risk stratification systems have been proposed to cover these limitations and provide to thyroidologists an easy‐to‐use tool guide for their clinical practice . As a proof of concept, these systems have shown a good performance in identifying suspicious thyroid nodules to be submitted to fine needle aspiration cytology (FNAC) .…”

“…The use of fluorine‐18‐fluorodeoxy‐glucose ( 18 F‐FDG) positron emission tomography/computed tomography (PET/CT) has significantly spread during the last years. In differentiated thyroid cancer (DTC), 18 F‐FDG PET/CT has reached a role for the assessment of patients with DTC suspicious for relapse and negative 131 I‐whole body scan . Also, in the field of thyroid nodule, several papers showed that FDG avid thyroid lesions incidentally detected during PET/CT acquisitions for oncologic purpose carry high risk of malignancy .…”

False negative rate of fine‐needle aspiration in thyroid nodules: impact of nodule size and ultrasound pattern

“…Although FTC accounted for only 27% of malignant tumors with false negative FNA results in nodules <3 cm, all malignant tumors with false negative FNA results were FTC in large nodules ≥3 cm and all of them showed an intermediate suspicion ultrasound pattern. Compared with PTC, suspicious ultrasound features such as microcalcification, non‐parallel orientation, spiculated/microlobulated margin are uncommon in FTC and FTC mostly shows intermediate or low suspicion ultrasound patterns (K‐TIRADS 4 or 3) …”