title: Improving diagnosis of tumor-induced osteomalacia with Gallium-68 DOTATATE PET/CT.
abstract: BACKGROUND
  Tumor-induced osteomalacia (TIO) is a rarely diagnosed disorder presenting with bone pain, fractures, muscle weakness, and moderate-to-severe hypophosphatemia resulting from fibroblast growth factor 23-mediated renal phosphate wasting. Tumors secreting fibroblast growth factor 23 are often small and difficult to find with conventional imaging.
  
  
  OBJECTIVE
  We studied the utility of (68)Ga-DOTA-octreotate (DOTATATE) somatostatin receptor positron emission tomography (PET)/computed tomography (CT) imaging in the diagnosis of TIO.
  
  
  METHODS
  A multicenter case series was conducted at tertiary referral hospitals.
  
  
  METHODS
  Six patients with TIO diagnosed between 2003 and 2012 in Australia were referred for DOTATATE PET imaging. We reviewed the clinical history, biochemistry, imaging characteristics, histopathology, and clinical outcome of each patient.
  
  
  RESULTS
  Each case demonstrated delayed diagnosis despite severe symptoms. DOTATATE PET/CT imaging demonstrated high uptake and localized the tumor with confidence in each case. After surgical excision, there was resolution of clinical symptoms and serum phosphate, except in one patient who demonstrated residual disease on PET/CT. All tumors demonstrated high somatostatin receptor subtype 2 cell surface receptor expression using immunohistochemistry.
  
  
  CONCLUSIONS
  In patients with TIO, DOTATATE PET/CT can successfully localize phosphaturic mesenchymal tumors and may be a practical first step in functional imaging for this disorder. Serum phosphate should be measured routinely in patients with unexplained muscle weakness, bone pain, or stress fractures to allow earlier diagnosis of TIO.
authors.affiliation: Cancer Genetics Unit, Hormones and Cancer Group, Kolling Institute of Medical Research, Royal North Shore Hospital, Sydney, New South Wales 2065, Australia.
authors.forename: Roderick J
authors.initials: RJ
authors.lastname: Clifton-Bligh
authors.forename: Michael S
authors.initials: MS
authors.lastname: Hofman
authors.forename: Emma
authors.initials: E
authors.lastname: Duncan
authors.forename: Ie-Wen
authors.initials: IeW
authors.lastname: Sim
authors.forename: David
authors.initials: D
authors.lastname: Darnell
authors.forename: Adele
authors.initials: A
authors.lastname: Clarkson
authors.forename: Tricia
authors.initials: T
authors.lastname: Wong
authors.forename: John P
authors.initials: JP
authors.lastname: Walsh
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Gill
authors.forename: Peter R
authors.initials: PR
authors.lastname: Ebeling
authors.forename: Rodney J
authors.initials: RJ
authors.lastname: Hicks
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005710:Gallium Radioisotopes; D006801:Humans; D008297:Male; D008875:Middle Aged; D009372:Neoplasms, Connective Tissue / Q000150:complications* / Q000000981:diagnostic imaging; D015282:Octreotide / Q000031:analogs & derivatives*; D009942:Organometallic Compounds; D010018:Osteomalacia / Q000000981:diagnostic imaging* / Q000209:etiology; D011877:Radionuclide Imaging
chemical_list: C499142:Ga(III)-DOTATOC; D005710:Gallium Radioisotopes; D009942:Organometallic Compounds; D015282:Octreotide