HYPERCALCEMIA OF MALIGNANCY: SIMULTANEOUS ELEVATION IN PARATHYROID HORMONE-RELATED PEPTIDE AND 1,25 DIHYDROXYVITAMIN D IN SARCOMA

ABSTRACT Objective Hypercalcemia is a common finding in patients who have an underlying malignancy. Only a few cases of hypercalcemia of malignancy have been linked to more than 1 mechanism of hypercalcemia. Here, we present a patient with liposarcoma and hypercalcemia of malignancy in the setting of simultaneous elevations in parathyroid hormone-related peptide (PTHrP) and 1,25 dihydroxyvitamin D [1,25(OH)2D] levels. Sarcoma-associated hypercalcemia is a rare disorder. Methods The patient was an 89-year-old woman with rare sarcoma-associated hypercalcemia. Multiple mechanisms were uncovered, and treatments were adjusted for them. Literature search for hypercalcemia of malignancy with multiple mechanisms was conducted. Results This is the first report describing dual mechanisms of sarcoma-associated hypercalcemia and only the fifth report on PTHrP and 1,25(OH)2D simultaneously causing hypercalcemia of malignancy. Conclusion Based on this finding, we recommend measuring the 1,25(OH)2D levels in conjunction with the PTHrP level in patients with malignancy as this would allow for a more proactive approach to the diagnosis and treatment of hypercalcemia of malignancy.