Answers

Asymptomatic hypercalcemia in an otherwise asymptomatic patient is most often caused by primary hyperparathyroidism. If the parathyroid glands are normal, secretion of PTH is suppressed by hypercalcemia. Granulomas and some lymphomas express 1-α-hydroxylase and activate vitamin D to produce excess 1,25-(OH)2-D, the mediator of the hypercalcemia. 25-(OH)-D levels are typically normal.