Hyperparathyroidism due to eutopic PTH secretion from an ectopic intrathymic parathyroid cyst.

Parathyroid cysts rarely cause hyperparathyroidism. In addition, they rarely occur in the thymus. We report a 56-year-old woman with hypertension on telmisartan and hydrochlorothiazide, who developed symptomatic hypercalcemia for a month.