Orthopedic surgical treatment of osteomalacia induced by culprit soft tissue tumor in the hip region: a single-center retrospective study.

Background: Due to its occult position, complex anatomical structure, and spatial relationships, the causative tumor of Tumor-Induced Osteomalacia (TIO) in the hip region is quite difficult to detect and qualitatively diagnose in clinical practice. In this regard, clinicians often lack sufficient knowledge about such tumors, leading to frequent missed diagnoses, misdiagnoses, and unreasonable treatment.

Objective: This study aimed to investigate the clinical characteristics of TIO patients with culprit soft tissue tumors in the hip region and evaluate the effect of surgical treatment on these individuals to improve clinicians' understanding of the rare phenomenon.

Methods: The clinical data of all patients, from January 2013 to January 2023, who underwent surgical treatment for hip located culprit soft tissue tumors by the subspecialty group on bone and soft tissue tumors at our institution, were retrospectively analysed. Specifically, the clinical characteristics and therapeutic effects were examined and the patients' clinical experience was summarized.

Results: Twenty-two patients, who met the inclusion criteria, were included. All patients experienced varying degrees of bone pain, commonly accompanied by weakness (16/22) and limited mobility (21/22), and 10 patients (45.5%) experienced a significant reduction in body height during the course of the disease. All patients underwent orthopedic surgery in the hip region, as hypophosphatemia occurred in all of them. Pathological diagnosis was confirmed to be consistent with causative tumors of TIO. All patients experienced a gradual increase in serum phosphorus postoperatively during short-term follow-up. The follow-up period was between 1 and 10 years, and the postoperative serum phosphorus levels were monitored at our hospital or other facilities close to the patients.

Conclusions: Oncogenic soft tissue tumors for TIO in the hip region are occult, making clinical misdiagnoses or missed diagnoses highly likely. Therefore, enhancing the clinician's understanding of this rare condition is imperative. Notably, for TIO patient whose culprit tumor can be located, complete surgical resection of the causative tumor is the best treatment option. Furthermore, close postoperative monitoring of serum phosphorus is necessary, and patients should be subjected to long-term follow-up for prompt detection of recurrent conditions.