Abstract: Background and purpose: This study investigated the value of cervical ultrasound and TSH-suppressed thyroglobulin in the diagnosis of recurrence or metastasis of differentiated thyroid carcinoma (DTC). Methods: This study analyzed the data on 196 thyroid carcinoma patients who underwent neck dissection after clinically suspecious recurrence of DTC in Peking Union Medical College Hospital from Aug. 2010 to Dec. 2014. Among the 196 patients, 62 patients sonographically suspecious recurrence after total thyroidectomy and/or radioactive iodine ablation therapy were enrolled in this study. The ultrasonic features of lymph node involvement were retrospectively analyzed. The value of the ultrasonic features in the diagnosis of lymph node involvement and a TSH-suppressed serum Tg level in the diagnosis of recurrence or metastasis of DTC was also evaluated. Results: Of the 62 patients, 59 were pathologically confirmed with lymph node involvement, 1 case with local recurrence and 2 cases without recurrence or metasta-thyroidsis. There were 121 ultrasonographically suspected lymph nodes, confirmed by pathology, 92 were metastatic ltsions, 25 were non-metastatic, 3 were fibrous tissue and 1 was striated muscle. The positive predictive rate of cyst, calcification or hyper-echogenicity in cortex was 100% in the diagnosis of lymph node involvement. There was a significant difference in disordered vascularity and cyst in cortex between metastatic and non-metastatic lymph nodes. Forty-nine patients were positive for Tg, whereas 13 were negative. The accuracy, sensitivity and specificity of TSH-suppressed serum Tg in the diagnosis of recurrence or metastasis of DTC were 82.3%, 81.7% and 100%. Conclusion: The disordered vascularity and cyst in cortex of the lymph node are highly specific indexes in diagnosing lymph node involvement. TSH-suppressed serum Tg level has high diagnostic value for detection of recurrence or metastasis of DTC. Cervical ultrasound can identify recurrent or metastatic lesions in both Tg-positive and Tg-negative patients.

Key words: Differentiated thyroid carcinoma, Recurrence, Cervical ultrasound, Thyroglobulin