OSTEOMALACIA REVEALING A SYNOVIAL SARCOMA OF THE NASAL CAVITY

D. Kaffel*, I. Cherif, R. Dhahri, S. Miladi, W. Hamdi, A. El May and M. M. Kchir

ABSTRACT

Oncogenic osteomalacia is an acquired, rare paraneoplastic syndrome characterized by renal phosphate wasting and subsequent hypophosphatemic osteomalacia. We report a case of oncogenic osteomalacia associated with a phosphaturic mesenchymal tumor in a 41-year-old woman. She presented with pelvicrural pain. There was also a lateral-left nasal swelling 3 cm in diameter with no other symptoms. BMD revealed a remarkable decrease in lumbar spine BMD (Tscore to - 5.2 DS). Radiologic examination showed multiple pathologic fractures of the pelvis. Severe hypophosphatemia, hyperphosphaturia, low plasma 1,25-dihydroxyvitamin D3 level were disclosed at presentation. Computed tomography of the facial bones showed a large tumor formation of the left nasal cavity in connection with a synovial sarcoma (SyS) confirmed by immunohistochemistry. After removal of the tumor, - biochemical and hormonal abnormalities disappeared with remarkable symptomatic improvement. In conclusion, although an extremely rare disease, clinicians and pathologists should be aware of the existence of Tumor induced osteomalacia.

Keywords: oncogenic osteomalacia; tumor induced osteomalacia; causes of osteoporosis; causes of low BMD; mesenchymal tumor; synovialosarcoma.