Surgical and biochemical outcomes of phosphaturic mesenchymal tumors causing tumor-induced osteomalacia in the head and neck region

Objectives: We aimed to report the surgical outcomes of phosphaturic mesenchymal tumors causing tumor-induced osteomalacia in the head and neck. Design: A retrospective cohort study Setting: A tertiary care academic hospital Methods: This study analyzed nine patients who underwent surgical excision of phosphaturic mesenchymal tumors in the head and neck region. The primary sites were two in the maxilla and ethmoid sinus, and one in the intracranial, skull, parotid gland, maxillary sinus, and nasal cavity in each patient. Outcomes were compared with those in the extremities and trunk (n = 32). Results: Five of nine patients (56%) developed residual disease/local recurrence associated with low serum phosphate level after initial surgical excision. At the last follow-up, the biochemical parameters were normalized in four of the five patients after re-excision without any medication. The local recurrence/residual disease risk was significantly higher for the head and neck compared with the extremities and trunk (56% vs. 25%, p = 0.048). The rate of remission (normalized serum phosphate without medication) at final follow-up was similar in both groups after re-excision (head and neck vs. extremities and trunk, 86% vs. 73%, p = 0.827). Conclusions: Phosphaturic mesenchymal tumor resection in the head and neck region was challenging because of its complex anatomy and proximity to the brain or other crucial organs, which was associated with high local recurrence/residual disease rate. However, biological remission was achieved in the majority of the patients after re-excision.