title: Advanced prostate cancer as a cause of oncogenic osteomalacia: an underdiagnosed condition.
abstract: OBJECTIVE
  Tumor-induced osteomalacia (TIO) is a paraneoplastic bone mineral disturbance related to fibroblast growth factor 23 (FGF23) overproduction by the tumor, usually from mesenchymal origin. Such condition leads to high phosphate renal wasting and, consequently, to cumbersome symptoms as weakness, bone pain, and fractures.
  
  
  METHODS
  Case report.
  
  
  RESULTS
  We report a case of an advanced castration-refractory prostate cancer patient, which developed severe hypophosphatemia with elevated phosphate excretion fraction. TIO was suspected, and increased levels of FGF23 reinforced such diagnosis. The patient died 4 months after being diagnosed with TIO.
  
  
  CONCLUSIONS
  This case suggests that TIO has a dismal prognosis in prostate cancer patients. The clinical oncology community must be aware about such disturbance that can be present in those patients with weakness, bone pain, and hypophosphatemia.
authors.affiliation: Clinical Oncology, Instituto do Câncer do Estado de São Paulo, São Paulo, Brazil.
authors.forename: Milena Perez
authors.initials: MP
authors.lastname: Mak
authors.forename: Verônica Torres
authors.initials: VT
authors.lastname: da Costa e Silva
authors.forename: Regina Matsunaga
authors.initials: RM
authors.lastname: Martin
authors.forename: Antonio Marcondes
authors.initials: AM
authors.lastname: Lerario
authors.forename: Luis
authors.initials: L
authors.lastname: Yu
authors.forename: Paulo Marcelo Gehm
authors.initials: PM
authors.lastname: Hoff
authors.forename: Gilberto
authors.initials: G
authors.lastname: de Castro
mesh_terms: D001938:Brazil; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood; D006801:Humans; D017674:Hypophosphatemia / Q000097:blood; D008297:Male; D008875:Middle Aged; D009372:Neoplasms, Connective Tissue / Q000175:diagnosis / Q000209:etiology* / Q000556:secondary*; D010018:Osteomalacia; D010257:Paraneoplastic Syndromes; D011471:Prostatic Neoplasms / Q000097:blood / Q000150:complications* / Q000473:pathology
chemical_list: C000717427:FGF23 protein, human; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23