Persistent hyperparathyroidism due to mediastinal parathyroid adenoma treated with selective arterial embolization with embosphere: first case in the literature

Primary hyperparathyroidism (PHPT) is the most common cause of hypercalcemia in the clinical setting and affects 0.3% of the population. Parathyroidectomy is the only definitive cure. Unfortunately, even in the most experienced hands, persistent primary hyperparathyroidism (P-PHPT) occurs in 4.7% of the patients. Ectopic adenomas are difficult to localize before and during operation and usually end up with P-PHPT. Herein, we presented a case with P-PHPT due to mediastinal parathyroid adenoma that was successfully ablated with selective arterial embolization. A 57-year-old female patient was admitted to our endocrinology clinic with persistent hypercalcemia 4 months after the initial surgery for PHPT that had been performed in another center. The patient did not accept the second operation, and serum calcium and parathyroid hormone (PTH) remained high despite medical treatment with cinacalcet and IV zoledronate. In the 99-m Tc-MIBI scintigraphy with SPECT, a 18 × 12-mm-sized lesion in the mediastinum at the paratracheal region was detected which was confirmed to be a possible parathyroid adenoma with fluorocholine PET and chest computed tomography (CT). The right bronchial artery that was detected to supply the mediastinal mass in CT angiography was selectively catheterized and embolized with embosphere. Right after the procedure, serum PTH and calcium levels were normalized and remained normal in 23 months of follow-up. Selective arterial embolization is a treatment option for ectopically located adenomas which are difficult to resect and in cases with certain comorbidities which constitute a contraindication for surgery.