PTH and parathyroid gland carcinoma: Primary hyperparathyroidism (PHPT) is a common endocrine disease, characterized by a generalized imbalance of calcium and phosphate, due to the excessive secretion of the parathyroid hormone (PTH), commonly caused by a solitary benign adenoma, and less frequently by either multiple adenomas or hyperplasia, and rarely by parathyroid carcinoma.