Idiopathic calcitriol-induced hypercalcemia. A new disease entity?

We describe 3 patients with a prolonged history of hypercalcemia. The patients did not take any vitamin supplements. All patients had low parathyroid hormone (PTH), high calcitriol (1,25(OH)2D3), and high angiotensin-converting enzyme (ACE) blood levels. There was no evidence of sarcoidosis of any other underlying disease in the results of an extensive workup. Treatment with prednisone resulted in normalization of calcium levels in all patients. They remained dependent on low-dose prednisone on a subsequent prolonged follow-up.