Endocrine Abstracts

Introduction: Lymph node (LN) metastases of papillary thyroid carcinoma (PTC) usually happen in the paratracheal and internal jugular chain and are unusual in the parapharyngeal space (PPS). Our aim is to emphasize on the possibility of parapharyngeal metastatic LNs in PTC and to describe the diagnosis methods, treatment options, and impact on the prognosis.

Case Report: A 62-year-old woman presented with a dysphagia lasting for 2 years. Examination revealed an anterior neck mass. On ultrasound, it was an EU-TIRADS 5 left thyroid nodule. Consequently, the patient underwent a total thyroidectomy with a bilateral central dissection and a left selective neck dissection (II-IV). Histopathologic examination of the thyroid gland confirmed the diagnosis of a PTC of the left lobe with metastasis on central and lateral LN dissections. The tumor was staged as pT2 N1b M0. Postoperatively, she had radioactive iodine ablation therapy. She received a cumulated dose of 200 mCi (2 courses). Ultrasound and thyroid scintigraphy were normal. However, because of a high thyroglobulin (TG) level, a CT scan was performed (3 months postoperatively) and showed a left 3–cm prestyloid mass. The mass was hypodense, with some irregular areas of enhancement: a parapharyngeal metastatic LN was suspected. The patient did not present any symptom related to the mass. On physical examination, there was no evidence of cervical lymphadenopathy, no palpable thyroid lesion, no cranial nerve deficits. The oropharyngeal exam was normal. A surgical resection of the mass was performed with external cervical approach: a mass measuring 3 × 2 cm was found in the left prestyloid space. On histopathologic examination, the mass was a metastatic LN of a PTC. Three months after the surgery, the patient was doing fine, with no evidence of disease.

Conclusion: PPS metastases from thyroid carcinoma are uncommon, and only few cases have been reported in the medical literature. These PPS LNs are not included during nodal dissection. If these areas are left undissected, they might be the cause of a persistent disease or a delayed recurrence. As a result, for patients with PTC, especially those who underwent neck dissection and have an unexplained increase in serum TG levels, CT or MRI should be done for surveillance rather than ultrasound to detect the presence of nodes in this compartment.