Introduction: Elevated plasma calcium level in patients diagnosed with primary hypoparathyroidism is a rare finding, resulting in most cases from the treatment with excessive doses of either vitamin D or its derivatives, or calcium salts.
Case: We report a case of a woman who developed severe hypercalcemia due to metastatic lung cancer, describing diagnostics strategies undertaken in this patient. Pamidronate treatment with subsequent chemotherapy resulted in a transient normalization of plasma calcium levels.
Conclusion: Our report shows that the presence of malignancy should always be taken into consideration in hypoparathyroid patients in whom plasma calcium levels increase and that the assessment of plasma levels of parathyroid hormone related peptide may be helpful in the differential diagnosis of hypercalcemia.