A rare cause of atraumatic fractures: case series of four patients with tumor-induced osteomalacia

Debbie W Chen,Palak U Choksi,Michael T Collins,Gregory A Clines,Liselle Douyon

doi:10.1186/s40842-020-00101-8

Abstract

BackgroundTumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome that presents with hypophosphatemia, bone pain, muscle weakness and fractures. We report a case series of four patients with TIO that resulted in significant muscle weakness and multiple atraumatic fractures.Case presentationFour patients were referred to an endocrinology clinic for the evaluation of multiple atraumatic fractures, muscle weakness, generalized muscle and joint pain. Laboratory evaluation was notable for persistent hypophosphatemia due to urinary phosphate wasting, low to low-normal 1,25-dihydroxyvitamin D, elevated alkaline phosphatase and elevated fibroblast growth factor 23 (FGF23). Tumor localization was successful, and all four patients underwent resection of phosphaturic mesenchymal tumors. Post-operatively, patients exhibited normalization of serum phosphorus, in addition to significant improvement in their ambulatory function.ConclusionHypophosphatemia with elevated FGF23 and low 1,25-dihydroxyvitamin D level in the setting of multiple atraumatic fractures necessitates careful evaluation for biochemical evidence of tumor-induced osteomalacia.

Highlights

Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome that presents with hypophosphatemia, bone pain, muscle weakness and fractures
Tumor-induced osteomalacia (TIO), known as oncogenic osteomalacia, is a rare paraneoplastic syndrome that presents with bone pain, muscle weakness, and fractures [1]
We report a case series of four patients from a single institution who were referred for unexplained fractures and subsequently diagnosed with TIO

Summary

Conclusion

Among adults with multiple atraumatic fractures, muscle weakness, and bone pain, the diagnosis of TIO should be considered and serum phosphorus, 1,25-dihydroxyvitamin D, and FGF23 levels checked.

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