CYP27B1 and hypercalcemia disease: Immunohistochemistry revealed strong expression of parathyroid hormone-related protein (PTHrP) and 25-hydroxyvitamin D3-1α-hydroxylase (CYP27B1), indicating potential contributions from both humoral and vitamin D-mediated pathways. The patient received supportive treatment with diuretics, calcitonin, and denosumab, which successfully corrected hypercalcemia.