Diagnostic Challenges in Oncogenic Osteomalacia due to Intracranial Phosphaturic Mesenchymal Tumor

Case: A 37-year-old man presented with multiple fragility fractures and profound weakness. Evaluation revealed hypophosphatemia and an elevated serum fibroblast growth factor-23. A Ga-68 DOTANOC PET-CT localized a phosphaturic mesenchymal tumor in the sphenoid bone. Surgical resection was performed with immunohistochemistry confirming the diagnosis and leading to rapid biochemical normalization. The patient showed progressive fracture healing and made a complete functional recovery by 12 months. Conclusion: Intracranial phosphaturic mesenchymal tumors are a rare cause of tumor-induced osteomalacia. This case underscores that in patients with unexplained fractures, systematic serum phosphate testing is critical. Functional imaging is essential for tumor localization, and complete surgical excision is curative.