Hypercalcemia with excess serum 1,25 dihydroxyvitamin D in lymphomatoid granulomatosis/angiocentric lymphoma. Hypercalcemia has been described in a variety of granulomatous and lymphoproliferative disorders in association with elevated serum levels of 1,25-dihydroxyvitamin D. In such cases, hypercalcemia appears to be the consequence of excessive production of 1,25(OH)2D by the lymphocyte/macrophage line. The authors report a patient with lymphomatoid granulomatosis/angiocentric lymphoma who developed hypercalcemia with extreme elevation in serum 1,25(OH)2D. Therapy with steroids reduced the serum calcium and 1,25(OH)2D levels to normal. Hypercalcemia has not previously been reported in lymphomatoid granulomatosis/angiocentric lymphoma. The distinctive features of this malignancy, and the derangement in the metabolism of 1,25(OH)2D in lymphoproliferative disorders in general, are discussed. 