Burden of Disease in Pediatric Tumor-Induced Osteomalacia: A Literature Review.

Tumor-induced osteomalacia (TIO) is an ultra-rare, paraneoplastic syndrome caused by tumors secreting fibroblast growth factor 23 (FGF23). In children, TIO may be mistaken for more common causes of rickets and osteomalacia, including monogenic forms, leading to long diagnostic delays. This review aimed to identify evidence on the diagnostic journey and burden of TIO in pediatric patients. A literature review was conducted to identify publications reporting disease characteristics, investigations, treatments, and clinical outcomes in pediatric patients diagnosed with TIO. In total, 41 studies were included in the review, reporting on 46 pediatric patients. Mean age at presentation was 11.2 years (standard deviation [SD]: 4.6). The majority of individuals (60.9%) were male. The most commonly reported symptoms at presentation were pain (65.2%), weakness (47.8%), and impaired physical function (43.5%). Rickets was reported in 45.7% of patients and fractures in 34.8% of patients. Mean time from onset of symptoms to diagnosis was 4.3 years (SD: 2.6) and mean number of imaging procedures per patient was 5.4 (SD: 2.7). Low serum phosphate concentration for age was reported in 93.5% of patients at presentation. Attempted surgical resection was reported in the majority of patients (89.1%) and was successful in 60.9%. Pediatric-onset TIO is associated with a substantial symptomatic and healthcare burden. Increasing awareness of TIO in children may prevent delays in diagnosis, reduce the need for radiation-conferring tests, and lower morbidity due to effective management. Further research in this area is needed to address the scarcity of data available in pediatric patients.