What is hypercalcemia of malignanacy?

Tumor release of PTH-related peptide, less commonly caused by local osteolytic lesions and rarely overproduction of dihydroxycholecalciferol. Most common cause of hypercalcemia in hospitalizaed pt, low or undectable intact PTH level, easily distinguished from HPT, only a few cases of ectopic true production of PTH are reported.