Endocrine Abstracts

Background: Papillary thyroid carcinoma (PTC) commonly metastasis to paratracheal and jugular lymph nodes. Retropharyngeal lymph node metastasis (RPNM) from PTC are rare. The aim of this study is to discuss the feasibility of the treatment for PTC with RPNM in our institution.

Methods: Eight patients underwent surgical treatment for metastasis of thyroid papillary carcinoma to RPN that presented as a parapharyngeal or retropharyngeal mass at Severance hospital from 2010 to 2022. All patients had a history of total thyroidectomy as their initial treatment and 2 patients of all patients had synchronous lung metastases at primary diagnosis of PTC. Among them, 5 and 2 patients underwent had undergone ipsilateral and bilateral modified radical neck dissection, respectively as their initial treatment or the treatment for PTC recurrence. The remaining 1 patient undergone central compartment neck dissection only as the initial treatment. Of the 8 patients, 5 patients were identified to have RPL metastasis at primary diagnosis, the other 3 patients were at diagnosis of PTC recurrence.

Results: Metastatic RPN were successfully resected via transoral approach in all patients. The study group comprised of 6 females and 2 males with mean age of 38.13 ± 14.79 years. Mean follow-up was 67.98 ± 69.61 months. Five patients initially diagnosed PTC with RPNM underwent surgery and high-dose high-dose radioactive iodine (RAI). Three patients who diagnosed as PTC recurrence underwent RPN resection transorally and followed by high-dose RAI. All of the eight patients including two patients with lung metastasis repeatedly underwent high-dose RAI after the surgical treatment, and six patients who did not have lung metastasis were followed up with the normal range of on-Tg (mean 1.18 ± 2.19) and TgAb (mean 31.78 ± 44.70) and shows no local or distant recurrence.

Conclusions: Although the cases were rare, metastasis to the RPN should be considered at primary diagnosis and follow-up. Neck CT scan or MRI is recommended for the diagnosis of RPNM, because these metastases will be missed by routine neck US. Complete thyroidectomy combined with transoral RPN resection is feasible and safe method for PTC with RPNM.