Metastatic thyroid carcinoma to the parapharyngeal and retropharyngeal spaces: Systematic review with seven newly reported cases describing an uncommon presentation of a common disease.

Abstract

Metastatic thyroid carcinoma to retropharyngeal and parapharyngeal (RP/PP) lymph nodes is rare. Literature suggests previous lateral neck dissection (LND) may alter patterns of lymphatic drainage in the neck, predisposing to these less common sites of spread. PRISMA-guided systematic search for all published cases detailing RP/PP metastases of well-differentiated thyroid carcinoma from 1970 to 2019. Seventy articles were identified and 44 were included, along with seven cases treated at our institution, totaling 239 cases. Cases represented both retropharyngeal (60.7%) and parapharyngeal (39.3%) metastases identified in the initial (27.6%) and recurrent (72.4%) setting. RP/PP metastases generally present in the recurrent setting. RP/PP metastases often represent high-risk disease, and surgical treatment is recommended.