FGF23 and hypophosphatemia: Oncogenic osteomalacia is known as a rare and curable cause of osteomalacia characterized by increased renal phosphate excretion and hypophosphatemia.[1] PMT is a rare neoplasm arising in bone and soft tissue that inappropriately produces FGF23, which has phosphaturic activity inhibiting renal tubular reabsorption of phosphate and renal conversion of 25-hydroxyvitamin D3 to 1,25-dihydroxyvitamin D3 (active form of vitamin D).