Hypercalcemia is caused by all except

Hyperparathyroidism is overactivity of the parathyroid glands resulting in excess production of parathyroid hormone (PTH). The parathyroid hormone regulates calcium and phosphate levels and helps to maintain these levels. Excessive PTH secretion may be due to problems in the glands themselves, in which case it is referred to as primary hyperparathyroidism and which leads to hypercalcemia.Secondary bone metastasis is a tumor found in bone. The clinical aphorism, a malignancy in bone in patients above age 35 is considered metastatic until proven otherwise.Thyrotoxicosis the condition caused by excessive quantities of thyroid hormones it may be due to overproduction by the thyroid gland (as in Graves&; disease), overproduction originating outside the thyroid, or loss of storage function and leakage from the gland.Tamoxifen a nonsteroidal oral antiestrogen used as the citrate salt in the treatment and prophylaxis of breast cancer.Ref: Ganong&;s review of medical physiology; 24th edition; page no:-386