Diagnostic Algorithm for Metastatic Lymph Nodes of Differentiated Thyroid Carcinoma

• Main Authors: Sae Rom Chung, Jung Hwan Baek, Young Jun Choi, Tae-Yon Sung, Dong Eun Song, Tae Yong Kim, Jeong Hyun Lee
• Format: Article
• Language: English
• Published: MDPI AG 2021-03-01
• Series: Cancers
• Subjects: papillary thyroid carcinoma; neoplasm metastasis; ultrasonography; biopsy; fine-needle; thyroglobulin
• Online Access: https://www.mdpi.com/2072-6694/13/6/1338

We aimed to evaluate appropriate strategies for interpreting fine-needle aspiration cytology (FNAC) and thyroglobulin concentrations obtained through aspiration (FNA-Tg) results based on the sonographic features of lymph nodes (LNs). Consecutive patients who underwent ultrasound-guided FNAC and FNA-Tg for metastatic LNs from differentiated thyroid carcinomas (DTCs) from January 2014 to December 2018 were reviewed retrospectively. LNs were categorized sonographically as suspicious, indeterminate, or benign. The optimal FNA-Tg cutoff for metastatic LNs was evaluated preoperatively, after lobectomy, and after total thyroidectomy. The diagnostic performances of FNA-Tg, FNAC, and their combination were analyzed based on the sonographic features of LNs. The malignancy rates of LNs were analyzed based on the sonographic features, FNAC, and FNA-Tg results. Of the 1543 LNs analyzed, 528 were benign, whereas 1015 were malignant. FNA-Tg increased the sensitivity and accuracy of FNAC for LNs. The malignancy rate of LNs found to be malignant by FNAC or elevated FNA-Tg ranged from 82% to 100%, regardless of the sonographic features. The malignancy rate of LNs with indeterminate or benign FNAC findings and low FNA-Tg were stratified according to their sonographic features. We propose a diagnostic algorithm, based on combined FNAC, FNA-Tg, and ultrasound features of LNs, for diagnosing metastatic LNs of DTCs.