A challenging case of hypercalcemia

The authors report a case of hypercalcemia in a 79-year-old woman that led to multiple hospitalizations. The case was challenging because the hypercalcemia was ultimately found to have 2 distinct causes. The patient initially presented with an elevated parathyroid hormone (PTH) level, consistent with primary hyperparathyroidism. She underwent parathyroidectomy and her hypercalcemia resolved in the immediate postoperative period. Four days after the operation, she was found to have recurrent hypercalcemia with a suppressed PTH level, raising suspicion for hypercalcemia of malignancy. After an extensive workup, the patient was found to have lymphoma, which was causing hypercalcemia and suppressing PTH. The authors also review the literature on hypercalcemia of malignancy.