Hypercalcemia of malignancy with simultaneous production of parathyroid hormone-related peptide and 1,25-Dihydroxyvitamin D by non-Hodgkin lymphoma: Case report & brief review

Abstract

We report the case of a 63-year-old man with severe hypercalcemia, acute kidney injury, and concomitant diagnosis of germinal center diffuse large B-cell lymphoma (nHL). Hypercalcemia is a common finding in patients with cancer. Multiple mechanisms can lead to hypercalcemia of malignancy, and different malignancies are often associated with a specific mechanism of hypercalcemia. Parathyroid hormone-related protein (PTHrP) and excessive production of 1,25-dihydroxyvitamin D can independently (and rarely, concomitantly) lead to development of hypercalcemia in patients with a variety of malignancies. Literature review of hypercalcemia related with PTHrP and 1,25-dihydroxyvitamin D co-secretion shows that most reported cases are associated with solid tumors and responded to tumor directed therapy. Our case of nHL was associated with increased PTHrP and 1,25-dihydroxyvitamin D making this an unusual presentation.