Cervical soft tissue recurrence of differentiated thyroid carcinoma after thyroidectomy indicates a poor prognosis

We investigated cervical soft tissue recurrence of differentiated thyroid carcinoma (DTC) after thyroidectomy, and these lesions exhibited no evidence that they were lymph nodes (LNs).

Between January 2012 and April 2016, consecutive 6308 patients underwent thyroid surgery for DTC at our center. Among them, we encountered 21 patients with recurrent cervical soft tissue lesions, none of whom had previously undergone fine needle aspiration biopsy (FNAB).

The 21 patients accounted for 0.33% of all 6308 patients, including twenty cases of papillary thyroid carcinoma and one case of follicular thyroid cancer. Approximately half (52.3%) of the recurrence were first detected by ultrasound (US). Eighteen lesions underwent complete preoperative US, but 6 lesions were misdiagnosed as metastatic LNs by US. Therefore, 54 age- and gender-matched recurrent or persistent LNs derived from DTC were randomly selected from the same database. The soft tissue lesions (mean size, 2.30 cm) were larger than the LNs. Fewer hyperechogenic hila and punctuations were found in the group of soft tissue recurrence (P < 0.05). During follow-up, distant metastasis was detected in 38.1% of patients in the soft tissue recurrence group. The distant metastasis rates showed that local soft tissue recurrence led to a poorer prognosis than cervical LN persistence or recurrence (P = 0.00).

Although the incidence of DTC recurrence in cervical soft tissue was low, it may be a predictor for distant recurrence. To minimize the risk, a long-term postoperative evaluation, preferably with US, should be performed.