(A649) Two Cases of Intra-vagal Parathyroid Adenomas

Introduction: Primary hyperparathyroidism is an endocrine disorder caused most commonly by single gland parathyroid adenoma. Intraneural parathyroid adenomas are exceptionally rare and can be challenging to identify. Our objective is to describe two cases of intra-vagal parathyroid adenomas in the post-styloid parapharyngeal space effectively treated with surgery and review the literature regarding intra-vagal parathyroid adenomas

Methods: This study is a case series, two cases are described and the literature is reviewed.

Results: One patient is a 35-year-old male with history of total thyroidectomy who underwent an unrevealing initial 4-gland exploration. Intraoperative venous sampling suggested right-sided adenoma and subsequent 4D CT scan revealed right skull base parathyroid adenoma. He underwent successful resection using intra-operative nerve monitoring with resolution of primary hyperparathyroidism and preservation of nerve function. The second patient is a 44-year-old female with primary hyperparathyroidism with pre-operative imaging revealing possible left carotid sheath adenoma which showed no avidity on SPECT-CT. She underwent venous sampling in the operating room which confirmed suspected location. She then underwent subsequent resection with resolution of primary hyperthyroidism and preservation of nerve function.

Conclusions: Intra-vagal parathyroid adenomas are an extremely rare cause of primary hyperparathyroidism. They can be located superiorly within the post-styloid parapharyngeal space. Venous sampling may help identify these adenomas and resection can be performed with preservation of vocal fold movement.