BACKGROUND: Tumor-induced osteomalacia is a rare and fascinating paraneoplastic syndrome usually caused by a small, benign phosphaturic mesenchymal tumor. Most tumors are treated surgically, but we are unaware of any reports that compare the results of curettage and segmental resection for lesions in long bones.METHODS: Seventeen patients (ten male and seven female) with tumor-induced osteomalacia lesions in long bones, who underwent surgical treatment from December 2004 to August 2013 in our hospital, were included in this retrospective study. The mean follow-up (and standard deviation) was 35 ± 27 months (range, twelve to 116 months). The characteristics of the tumor and the effects of different surgical treatments (curettage compared with segmental resection) were evaluated.RESULTS: All patients showed typical clinical characteristics of tumor-induced osteomalacia, including elevated serum fibroblast growth factor-23 (FGF-23); 82% of tumors were in the epiphysis, and 82% grew eccentrically. The mean maximum diameter of the tumors was 2.4 ± 2.0 cm. The complete resection rates were similar for curettage (67%) and segmental resection (80%). However, the recurrence rate after curettage (50%) was higher than that after segmental resection (0%). The complete resection rate for secondary segmental resection (75%) was not different from that for primary segmental resection (83%). All of our cases of tumor-induced osteomalacia were caused by phosphaturic mesenchymal tumors. After successful removal of tumors, serum FGF-23 returned to normal within twenty-four hours and serum phosphorus levels returned to normal at a mean of 6.5 ± 3.5 days.CONCLUSIONS: Most lesions in long bones are located in the epiphysis, so curettage is first suggested to maintain joint function. If curettage is incomplete or there is a recurrence, secondary segmental resection should be considered curative. Changes of serum FGF-23 and phosphorus levels before and after the operation may be of prognostic help.
Adult Bone Neoplasms