[Hypercalcemia as incidental finding--what should be done?].

The discovery of a hypercalcemia validated by exclusion of hemoconcentration and follow-up calcium determinations opens the differential diagnosis of a malignancy and of hyperthyroidism whereas drug-induced causes can be recognized easily. A single determination of plasmatic parathyroid hormone (PTH) allows to safely distinguish between PTH-induced or PTH-independent, most often tumor-associated hypercalcemia. In both instances the patient may be free of symptoms particularly the very old one. Therapeutic measures are indicated in both instances: Treatment of malignancy-associated hypercalcemia is clinically effective and treatment of asymptomatic hyperthyroidism is likewise recommended, mainly to preserve bone mass and cerebral performance.