Calcitriol levels in hypercalcemic patients with adult T-cell lymphoma.

Hypercalcemia is a frequent complication in patients with adult T-cell lymphoma. We measured serum calcitriol (1,25-dihydroxyvitamin D3) levels in five hypercalcemic patients with adult T-cell lymphoma and compared the values with those of five patients with mycosis fungoides, a T-cell neoplasm not associated with hypercalcemia. All five patients with adult T-cell lymphoma had calcitriol levels in or below the normal range. These data show that elevated calcitriol levels are not uniformly elevated in this disorder and may not be the usual cause of hypercalcemia in this subgroup of patients with lymphoma.