Occult papillary thyroid carcinoma presenting as parapharyngeal space mass: A case report and literature review

Papillary thyroid carcinoma presenting as a parapharyngeal mass is uncommon clinical presentation^1,2. Papillary thyroid cancer is the most common primary thyroid cancer (80–90 % of cases)¹⁷. 20–50 % of cases have lymph node metastasis⁴. Superior thyroid lesions usually metastasize through superior pretracheal and cervical nodes while inferior thyroid and isthmus drainage travel via the paratracheal and deep cervical nodes¹⁷. Parapharyngeal space (PPS) tumors are rare and represent about 0.5 % of all head and neck tumors^1,2. We report a case of 59 years-old man who presented initially with left parapharyngeal mass for about four months and a chief complaint of dysphagia. Exam revealed a submucosal 4 cm mass in the oropharyngeal wall, no tumor was palpable in the neck and his physical examination was otherwise unremarkable. Preoperative work up was completed, and Fine Needle Aspiration (FNA) was inconclusive. The mass was excised via transcervical-mandibular swing approach and a diagnosis of papillary thyroid carcinoma was rendered. Subsequently, the patient underwent a total thyroidectomy and neck dissection. This case report highlights the unusual metastasis to parapharyngeal space from occult papillary thyroid carcinoma, reviews the lymphatic drainage system of the head and neck responsible for this route of metastasis, recommendations for preoperative imaging, surgical treatment, and adjuvant treatment of this uncommon presentation.