Treatment and clinical features of tumor-induced osteomalacia:a retrospective review of fifteen patients
LI Wei1,WANG Xiangdang2,ZUO Qingyao1,WANG Hong1,HUANG Yanhong3,SONG Hui3,and DENG Wei1.
1.Department of Endocrinology;3. Department of Rheumatology,Jishuitan Hospital,Beijing 100035,China; 2.Department of Pharmacy,General Hospital of Chinese People’s Armed Police Force,Beijing 100039,China
Abstract：Objective To investigate the clinical features, diagnostic process and outcomes of tumor-induced osteomalacia (TIO).Methods A retrospective analysis of fifteen patients with TIO was performed, involving pre- and post-operative clinical features and biochemical changes.Results Among the fifteen patients, there were two cases of recurrence (13.3%)and one case of metastases (6%)after recurrence. The average age was (42.8±10.7 )years, and the mean duration of disease was (3.5±2.8 )years. Serum phosphorus concentrations were low in all these patients (0.41±0.10)mmol/L.The renal phosphate threshold (RTPC) decreased in all the patients with an average of (0.33±0.10) mmol/L. These patients were treated surgically nineteen times. Nine tumors were found in soft tissues and ten tumors in bones. Thirteen of these cases (86.7%) were cured through primary operation and serum phosphorus concentrations returned to normal in (3.7±1.6 )days. All the nineteen tumors were phosphaturic mesenchymal tumors of the mixed connective tissue variant. One case was found to be malignant during the follow-up. Compared with tumors in bones, tumors in soft tissues caused a lower serum phosphorus concentration and lower RTPC (t=2.264, P=0.041). Regression analysis showed that the blood phosphorus concentration was influenced primarily by RTPC (standardized beta coefficient=0.836, t=3.862,P=0.005), and that RTPC was influenced by tumor volume and tumor tissue origin (standardized beta coefficient=0.405、0.546,t=-2.635、3.925,P=0.030、0.004, respectively).Conclusions The chance of recurrence and metastasis of TIO is high. Compared with 24-hour urine phosphorus concentrations, RTPC is more suitable for the evaluation of impaired renal tubular function. Patients with a tumor in soft tissues are in more critical condition.
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2018, Vol. 29 
