Diagnostic value of thyroglobulin assay in cervical lymph node fine-needle aspirations for metastatic differentiated...

Differentiated thyroid cancers (DTCs) have generally an indolent behavior. However, in a minority of these patients cervical metastasis at diagnosis or recurrence during follow-up may occur. Then, in suspicious neck lymph nodes fine-needle aspiration (FNA) is warranted. Thyroglobulin measurement in needle washout fluids (FNA-Tg) since its first description has been reported to increase the diagnostic accuracy of cytology in neck lymph nodes suspicious for metastatic DTC.

Recent literature suggests that FNA-Tg can substitute conventional cytology and, in turn, simplifies clinical management of DTC patients. However, because of the large difference between these clinical studies, the data are sparse. Thus, neither procedures nor assay method for FNA-Tg have been standardized.

FNA-Tg measurement is the more accurate tool to detect neck recurrences and metastases from DTC. Providing strict standardization of preanalytical and analytical phase, FNA-Tg may suffice to confirm or exclude neck DTC recurrence in patients with concurrent well differentiated papillary cancer type, suspicious neck ultrasound findings and increased serum thyroglobulin after thyroidectomy. On the contrary, FNA-Tg accuracy increases by adding cytological examination when FNA is performed before thyroidectomy, in patients with more aggressive histological types, and if low-undetectable serum thyroglobulin and/or positive serum antithyroglobulin antibodies occur.