[Angiotensin-converting enzyme and 1,25-dihydroxyvitamin D3 in hypercalcemia of unknown origin]

Sarcoidosis of the kidneys and liver without radiologically demonstrable lung involvement in a 44-year-old woman was shown to be the cause of a hypercalcaemia syndrome. The hypercalcaemia was presumably due to an increased production of 1,25-(OH)2-vitamin D3 which--like the increased angiotensin converting enzyme--is produced in the epithelioid and giant cells. Corticoid treatment normalized serum calcium and ACE levels and improved renal function. These observations demonstrate that measurement of ACE and 1,25-(OH)2-vitamin D3 levels is helpful in the differential diagnosis of hypercalcaemia, in view of the possibility of sarcoidosis, and should be among the diagnostic tests.