Surgical Treatment of Tumor-Induced Osteomalacia With Causative Tumors Affecting the Long Bones

The causative tumor for tumor-induced osteomalacia (TIO) locating in the long bone is hidden and has diverse locations, resulting in great challenges to orthopedists. This study aimed to investigate and summarize the clinical features and surgical outcomes of TIO patients with culprit tumors involving the long bones to enhance clinical understanding and improve orthopedic surgical management of this rare disease.

A retrospective analysis was performed on the clinical data of TIO patients with causative tumors located in the long bones who underwent surgery by the Orthopedic Bone and Soft Tissue Tumor Sub-specialty Group at our hospital between January 2013 and January 2023. This article described the clinical symptoms, location of causative tumors, tumor sizes, and other clinical features of TIO patients, and analyzed the trend of changes in blood phosphorus levels before and after surgery and pathological results. At the same time, clinical surgical experience and strategies for TIO patients with culprit tumors located in long bones were summarized.

All 49 patients included in the study had been pathologically confirmed and met clinical diagnostic criteria for TIO. All patients experienced bone pain (49/49), often accompanied by limited mobility, fatigue, difficulty turning over, and difficulty sitting up or walking. Importantly, 65.3% (32/49) experienced height loss during disease progression. A total of 65 operations were performed on these 49 patients, with culprit tumors located in the humerus (five cases), femur (33 cases), tibia (seven cases), fibula (three cases), and foot (one case). Twenty-nine cases involved skeletal lesions, seven cases affecting the periosteum (outside-in), while 13 showed both bone and soft tissue involvement. Following the final orthopedic procedure, serum phosphorus levels increased in 45 patients, and the median follow-up duration was 45 months (interquartile range, 28-61 months; range, 2-215 months). Nine patients showed no remission after the first orthopedic surgery, and five experienced recurrence. One patient was diagnosed with a malignant culprit tumor.

Surgical planning for TIO with long bone involvement should account for the anatomical location and extent of the causative tumor. Currently, no standardized surgical strategy exists for this rare condition. Recurrence, non-remission, or malignant transformation remains possible due to incomplete resection or local relapse. Based on the single center experience of this case series, we summarized the surgical classification and feasible surgical strategies for TIO's orthopedic surgery with causative tumors located in the long bones. The actual clinical application effect of this classification system needs further clinical data verification.