What is the recommended workup for PTH-independent hypercalcemia secondary to an elevated 1,25-dihydroxyvitamin D level?

I presume what is meant is that the PTH is suppressed, and therefore, with an elevated 1,25-dihydroxyvitamin D concentration, it is likely the primary cause? The 2 major causes for elevated 1,25-dihydroxyvitamin D when serum 25-hydroxyvitamin D is normal or sometimes low are due to either a granulom...