Perioperative Anesthetic Considerations for Temporal Bone Tumor Resection in Fibroblast Growth Factor 23 (FGF23)-Related Tumor-Induced Osteomalacia: A Case Report.

Phosphaturic mesenchymal tumors (PMTs) are uncommon, predominantly benign neoplasms frequently associated with dysregulated phosphate metabolism through the overproduction of fibroblast growth factor 23 (FGF23). Elevated levels of FGF23 lead to phosphate depletion, which may impair tissue oxygen delivery, central respiratory drive, and respiratory muscle function. Systemic manifestations may include osteomalacia and neuromuscular dysfunction, with an increased risk of respiratory and cardiovascular complications. PMTs often present with nonspecific clinical findings and may remain unrecognized during the perioperative period, presenting significant challenges for anesthetic planning and management. We report the case of a 72-year-old male with tumor-induced osteomalacia (TIO), a right temporal mass, and multiple comorbidities, including hypertension and obstructive sleep apnea. The patient reported progressive headaches and general weakness. After neurosurgical evaluation, he underwent elective surgical excision under general anesthesia. Intraoperatively, he developed hypotension following induction of anesthesia, requiring vasopressor support with ephedrine boluses and a continuous phenylephrine infusion. The remainder of the procedure was uneventful, and the patient was extubated and transferred to the intensive care unit in stable condition. This case highlights the importance of recognizing potential complications in patients with metabolic abnormalities presenting with PMTs, particularly disturbances in phosphate homeostasis that may have significant anesthetic implications. The use of video laryngoscopy, judicious administration of neuromuscular blocking agents, and an individualized anesthetic strategy facilitated secure airway management, minimized cervical manipulation, and supported an uneventful recovery. Moreover, integrating anesthetic selection with comprehensive perioperative planning is essential to address the metabolic, musculoskeletal, respiratory, and hemodynamic challenges associated with TIO, particularly in patients with significant comorbidities.