Diagnostic Algorithm for Metastatic Lymph Nodes of Differentiated Thyroid Carcinoma

Area of Science:

• Endocrinology
• Oncology
• Radiology

Background:

• Accurate diagnosis of lymph node (LN) metastases is crucial in differentiated thyroid carcinomas (DTCs).
• Interpreting fine-needle aspiration cytology (FNAC) and fine-needle aspiration thyroglobulin (FNA-Tg) results can be challenging based solely on sonographic features.
• Optimizing diagnostic strategies is essential for effective patient management.

Purpose of the Study:

• To evaluate strategies for interpreting FNAC and FNA-Tg results in metastatic LNs from DTCs.
• To assess the diagnostic performance of FNA-Tg, FNAC, and their combination based on LN sonographic features.
• To develop a diagnostic algorithm for metastatic LNs in DTCs.

Main Methods:

• Retrospective review of patients with ultrasound-guided FNAC and FNA-Tg for metastatic LNs from DTCs (January 2014 - December 2018).
• LN categorization based on sonographic features: suspicious, indeterminate, or benign.
• Evaluation of optimal FNA-Tg cutoffs and analysis of diagnostic performances of FNA-Tg, FNAC, and their combination.

Main Results:

• Of 1543 LNs, 528 were benign and 1015 malignant.
• FNA-Tg improved the sensitivity and accuracy of FNAC for LN metastasis detection.
• High malignancy rates (82%-100%) were observed for LNs positive by FNAC or elevated FNA-Tg, irrespective of sonographic features.

Conclusions:

• A combined approach using FNAC, FNA-Tg, and ultrasound features provides a robust diagnostic strategy for metastatic LNs in DTCs.
• The proposed diagnostic algorithm can aid in accurate staging and treatment planning for DTC patients.
• Further refinement of diagnostic criteria based on combined modalities is recommended.