Abstract 35: An obscure cause of primary hyperparathyroidism: Series of three cases of ectopic parathyroid adenoma

Background and Objectives: Primary hyperparathyroidism is a common endocrine disease which can lead to significant morbidity. Parathyroidectomy is an effective treatment option for this condition. Ectopic parathyroid adenoma is the most common cause of persistent hyperparathyroidism after surgery and these lesions are difficult to localize by imaging as well as during exploration due to its variable location. We hereby describe three unique cases of primary hyperparathyroidism with variable clinical presentation and ectopic parathyroid adenomas. Methods and Results: This is a retrospective study and medical records of patients having primary hyperparathyroidism with ectopic parathyroid adenoma were retrieved from centralized hospital information processing system (CHIPS). Relevant bone mineral profile including serum calcium, phosphorus, albumin, 25 (OH)2 vitamin D, parathyroid hormone, alkaline phosphatase, creatinine and 24 hour urine calcium, phosphorus and creatinine and TmP/GFR was assessed. Radiological investigations including ultrasound neck, ultrasound abdomen, parathyroid scintigraphy and DXA scans were also assessed. 4-D CT neck was done in two cases where imaging findings on ultrasonography of neck and parathyroid scintigraphy were discordant. Carotid sheath, intrathyroidal and superior mediastinum were the sites where ectopic adenomas were localized. Two patients underwent multiple surgeries for persistent hyperparathyroidism as ectopic lesions were not localized initially. Conclusion: Ectopic parathyroid adenomaspose unique challenges in management of primary hyperparathyroidism. Combination of imaging i.e. ultrasound and sestamibi scan should be used to localize these adenomas and in case of discordance or non-localization, 4D CT of the neck can be helpful. Surgery in such cases should be performed by a high-volume parathyroid surgeon, who has ample experience in parathyroid surgeries.