A case of congenital agenesis of the common carotid artery associated with an ectopic parathyroid adenoma mimicking a carotid body tumor

Ectopic parathyroid adenomas can be encountered during four gland explorations, but nearly 80% of adenomas are localized with ultrasound and sestamibi imaging. Ectopic adenomas are thought to arise from abnormal migration during development. As a cervical congenital anomaly, common carotid artery agenesis is an extremely rare anomaly characterized by separate origins of the internal and external carotid arteries directly from the aortic arch. Here we present a case of a 75 year old man with primary hyperparathyroidism who was found to have congenital agenesis of the common carotid artery associated with an ectopic parathyroid adenoma within the parapharyngeal space, which mimicked a carotid body tumor based on location and imaging. The successful identification and resection of the ectopic parathyroid adenoma presented here demonstrate the importance of preoperative imaging studies to allow appropriate operative planning as well as the utility of intraoperative parathyroid hormone assay in predicting cure during surgery.