Humoral hypercalcemia due to gastric carcinoma secreting parathyroid hormone-related protein during chemotherapy: a case report.

Humoral hypercalcemia due to a gastric carcinoma-secreting parathyroid hormone-related protein (PTHrP) is a rare disease associated with poor prognosis. A 61-year-old male with gastric cancer who had been receiving chemotherapy showed serum hypercalcemia and an elevated level of serum PTHrP with a suppressed intact parathyroid hormone level. Computed tomography revealed stable disease 4 weeks prior, and the laboratory examination revealed no adverse effects 2 weeks prior. The biopsy at the time of diagnosis was immunohistochemically positive for PTHrP later. Despite intensive care, the patient died of multiorgan failure on the 14th day after admission. In case of undifferentiated gastric cancer, the possibility of humoral hypercalcemia of malignancy caused by gastric cancer should be considered even when the patient is receiving chemotherapy.