title: Ovarian cancer-related hypophosphatemic osteomalacia--a case report.
abstract: BACKGROUND
  Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome caused primarily by benign mesenchymal tumors. It has been associated with malignancies in rare cases. High serum levels of fibroblast growth factor (FGF) 23 reported in a group of patients with ovarian cancer had normal serum phosphate levels. There had been no ovarian cancer-related hypophosphatemic osteomalacia in a search of the literature.
  
  
  OBJECTIVE
  We investigated a 57-year-old woman with progressive low back pain.
  
  
  METHODS
  Clinical, biochemical, and radiological assessments were performed. The patient's serum phosphate and FGF23 levels were evaluated at baseline and after treatment for ovarian cancer.
  
  
  RESULTS
  The patient presented with progressive low back pain and weight loss during the previous 6 months. Imaging studies revealed low bone mineral density and multiple suspicious spinal metastatic lesions. Laboratory examination showed hypophosphatemia, hyperphosphaturia, normocalcemia, an elevated serum alkaline phosphatase level, and an elevated serum FGF23 level. Because TIO was suspected, a tumor survey was performed, and ovarian carcinoma with multiple metastasis was detected. After surgery and chemotherapy treatments for ovarian cancer, the serum phosphate and FGF23 levels returned to normal, and the low back pain improved.
  
  
  CONCLUSIONS
  To our knowledge, this is the first case of ovarian cancer-related hypophosphatemic osteomalacia reported in the literature. TIO should be considered in patients with ovarian cancer presenting with weakness, bone pain, and fractures. Investigation of TIO is appropriate when these patients present hypophosphatemia.
authors.affiliation: Lo-Sheng Sanatorium and Hospital (H.-A.L.), Ministry of Health and Welfare, New Taipei City 242, Taiwan; National Taiwan University College of Medicine (S.-R.S., K.-S.T.), Taipei 100, Taiwan; and Departments of Internal Medicine (S.-R.S., Y.-T.T., W.-Y.C., C.-Y.H., K.-S.T.) and Obstetrics and Gynecology (C.-H.C.), National Taiwan University Hospital, Taipei 100, Taiwan.
authors.forename: Hung-An
authors.initials: HA
authors.lastname: Lin
authors.forename: Shyang-Rong
authors.initials: SR
authors.lastname: Shih
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Tseng
authors.forename: Chi-Hau
authors.initials: CH
authors.lastname: Chen
authors.forename: Wei-Yih
authors.initials: WY
authors.lastname: Chiu
authors.forename: Chih-Yao
authors.initials: CY
authors.lastname: Hsu
authors.forename: Keh-Sung
authors.initials: KS
authors.lastname: Tsai
mesh_terms: D003131:Combined Modality Therapy; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood; D006801:Humans; D017674:Hypophosphatemia / Q000209:etiology*; D017116:Low Back Pain / Q000209:etiology; D008875:Middle Aged; D010018:Osteomalacia / Q000209:etiology*; D010051:Ovarian Neoplasms / Q000150:complications* / Q000628:therapy
chemical_list: C000717427:FGF23 protein, human; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23