Tumor-Induced Osteomalacia—An Elusive and Often Delayed Diagnosis: A Case Report

Case: A 62-year-old woman presented to an outside institution with a foot mass and pathologic femur fracture. Imaging studies demonstrated concern for a widely metastatic process. Bone biopsy demonstrated a granulomatous process with no evidence of malignancy. This case describes a unique presentation and a challenging diagnosis of tumor-induced osteomalacia (TIO) arising from a soft-tissue phosphaturic mesenchymal tumor (PMT) that required multiple subspecialist visits before reaching the final diagnosis. Conclusion: Surgical resection of the foot PMT was curative with no sequelae. This case demonstrates that TIO can present as mimicking a metastatic process.