Reliable neck sonography of nodal thyroglobulin to diagnose recurrent/persistent disease from papillary thyroid carcinoma

This study evaluates the correlation between the sonographic features and the nodal fine-needle aspiration thyroglobulin (FNA-Tg) in papillary thyroid carcinoma (PTC) patients with the recurrent/persistent lymph node for the purpose of the reasonable selection of lymph nodes.This study prospectively contained PTC patients with the suspicious cervical lymph nodes in one medical center from April 2018 to January 2019. Each suspected lymph node was aspirated with a 22-gauge needle and the value of FNA-Tg was measured as well.There were 136 lymph nodes related to the disease involved. The FNA-Tg levels of 89 (65.44%) metastatic lymph nodes were significantly higher than those of the benign. The median value of the former was 631.550 ng/mL while the latter was 0.056 ng/mL (p = 0.000). The cut-off value of the metastatic lymph nodes diagnosed by FNA-Tg was 2.71 ng/mL, and 6.5 by FNA-Tg/sTg. The suspicious ultrasonographic features including cystic, hyperechoic content, and lack of hilum were closely related to the high level of FNA-Tg value (p < 0.05). However, the round shape (Solbiati index <2) and calcification were not significantly correlated with the positive FNA-Tg (p > 0.05).FNA-Tg is an effective supplement to fine-needle aspiration (FNA) cytology in the nodal metastasis diagnosis. The FNA-Tg level was much higher in the metastatic lymph nodes. The reliable sonographic features of lymph nodes suggested the positive FNA-Tg were cystic content, hyperechoic content and lack hilum. Solbiati index <2 and calcification did not show an exact correlation with the result of FNA-Tg.