Parapharyngeal space metastasis of papillary thyroid carcinoma

Abstract

Background

The parapharyngeal space contains adipose tissue, lymphatics, cranial nerves, and blood vessels that can serve as a site of tumor metastasis, often via the retropharyngeal lymph nodes. Papillary thyroid carcinoma lymphatic spread is rare but aggressive in nature, and not well detailed.

Case report

We describe one patient with a 13-year past medical history of PTC treated with total thyroidectomy, neck dissection, and radiation who presented with PPS papillary adenocarcinoma. She presented with a 2-weeks of throat pain and dysphagia. She had not follow-up after PTC treatment due to limited care access. A PPS lesion was appreciated on CT, and the tumor demonstrated well-differentiated PTC in addition to high-grade carcinoma with squamous features. The lesion encased the carotid sheath structures and paravertebral fascia, making it inoperable. The patient's condition rapidly deteriorated she expired 74 days after the initial presentation.

Discussion

PTC is the most common thyroid carcinoma and usually spreads via lymphatic drainage. One possibility of metastasis could be via an anatomical variant in which the PPS and retropharyngeal spaces freely communicate. Our case supports the previously described route of metastasis via retrograde lymphatic drainage due to a cervical lymph node metastasis or neck dissection during the initial treatment of PTC 13 years prior.

Conclusion

Our case report highlights the aggression of papillary thyroid carcinoma metastasis to the PPS and emphasizes the need for consistent follow-up post-cancer treatment. Additional studies are required to determine if this metastasis occurred due to neck dissection or regional cervical lymph node involvement.