A Case of Carcinoid Tumor-Associated Hypercalcemia.

Hypercalcemia as a complication of carcinoid tumors is extremely rare. Accordingly, we report the case of a 55-year-old male with metastatic carcinoid tumor and hypercalcemia, which corrected when the patient was treated with octreotide for symptomatic relief of watery diarrhea. The etiology of the hypercalcemia is presumed to be a neoplastic expression of fibroblast growth factor-23, which was found to be inappropriately high-to-normal when other factors such as parathyroid hormone, calcitonin and vitamin D were appropriately low or low-to-normal.