ABSTRACT
Oncogenic octeomalacia is an unusual and rare clinicopathologic syndrome characterized by mesenchymal tumors that apparently produce osteomalacia and biochemical abnormalities consisting of hypophosphatemia and normocalcemia. We have investigated the mechanism by which a giant cell tumor of bone caused biopsy-proved osteomalacia in a 50-year-old woman. A 50-year-old woman presented with generalized bone and pelvicrural pain, associated with fatiguability and muscle weakness. The diagnosis of osteomalacia was retained, associated with a giant cell tumor. The coexistence of giant cell tumor of bone and osteomalacia suggested the diagnosis of oncogenic osteomalacia. Resolution of the biochemical abnormalities of the syndrome after tumor resection, established this diagnosis. oncogenic osteomalacia can be a form of vitamin-D-refractory osteomalacia due to altered vitamin D3 metabolism