Tumor-induced rickets-osteomalacia: an enigma

Abstract

ObjectiveWe report a case of pediatric thoracic tumor-induced osteomalacia (TIO) causing severe hypophosphatemic rickets with delayed diagnosis and emphasize on timely management of this rare entity.Case presentationA young boy presented with rickets since five years of age. Biochemical evaluation revealed hypophosphatemia, hyperphosphaturia, elevated alkaline phosphatase and normal calcium levels. Initially managed as hereditary hypophosphatemic rickets, he was given phosphorus supplements and calcitriol. Despite the therapy, skeletal deformities worsened requiring surgical corrections. Subsequently, he developed iatrogenic tertiary hyperparathyroidism for which he underwent total parathyroidectomy. Later on, he was found to have fibroblast growth factor-23 secreting thoracic mass (10.5 cm in largest dimension) which was excised with significant post operative improvement. Histopathology showed phosphaturic mesenchymal tumor-mixed connective tissue variant, confirming the diagnosis of TIO.ConclusionTIO, a correctable cause of hypophosphatemic rickets, should be considered in children presenting with hypophosphatemic rickets with evident mass on examination/imaging and in refractory cases.

Early Discrimination Between Tumor-Induced Rickets/Osteomalacia and X-Linked Hypophosphatemia in Chinese Children and Adolescents: A Retrospective Case–Control Study

“…The clinical and biochemical manifestations of TIR/O in children and adolescent patients most commonly reported in previous studies (3,(5)(6)(7)(8)(9)(10)(11)(12) are similar to the ones observed in our patients. However, some patients initially presented at a much younger age (9 months 5 years), (6,11,13) had an uncommon tumor location (intracranial lesion), (7) or had an atypical histopathology (central giant cell lesion).…”

“…TIR/O cases in children and adolescents are scarcely reported in the literature, either as case reports (5)(6)(7)(8)(9)(10)(11)(12)(13) or in reviews. (3,9) Our study comprehensively analyzed the clinical, biochemical, radiological, and pathologic findings associated with this rare entity in a large retrospective cohort of Chinese children and adolescents.…”

“…Although TIO can also occur in children and adolescents, data on these patients remain limited. (3,(5)(6)(7)(8)(9)(10)(11)(12)(13) In children and adolescents, TIO presentation can be dominated by rachitic manifestations rather than osteomalacic manifestations; for this reason, the term tumor-induced rickets/osteomalacia (TIR/O) is preferred. TIR/O in children and adolescents poses a great diagnostic challenge for physicians as it is often misdiagnosed as hereditary hypophosphatemic rickets/osteomalacia (HR/O), in particular as X-linked hypophosphatemia (XLH).…”

Imaging characteristics of phosphaturic mesenchymal tumors

“…The multifocality of these tumors makes it prudent to look for additional lesions on whole-body imaging in these cases, especially in cases that do not show improvement after resection. Although less commonly described, TIO should be kept in the differentials for children presenting with refractory hypophosphatemic rickets (34).…”

Phosphaturic Mesenchymal Tumor

“…Pediatric cases have been infrequently reported. 4 The median age at the time of diagnosis is 44-48 years of age. 5,6 Tumor locality is unpredictable; PMTs can be found in any osseous or soft-tissue location and uncommonly involve the skin.…”