PTH and Hypercalcemia: Contrary to parathyroid hyperplasia and adenomas, PCs are associated with poor prognosis due to more severely elevated PTH, and higher, commonly unmanageable, hypercalcemia, which accounts for death in a majority of cases, with an overall survival rate of 78-85% and 49-70% at 5 and 10 years after diagnosis, respectively (2).