title: The phosphaturic mesenchymal tumor: why is definitive diagnosis and curative surgery often delayed?
abstract: BACKGROUND
  Tumor-induced osteomalacia is a paraneoplastic syndrome resulting in renal phosphate wasting and decreased bone mineralization. Phosphaturic mesenchymal tumors represent a rare etiology of tumor-induced osteomalacia. Nonspecific symptoms of fatigue, bone pain, and musculoskeletal weakness make the diagnosis elusive and lead to a delay in surgical treatment.
  
  
  OBJECTIVE
  In this case series, the following three questions were asked: (1) How do the clinical presentation and features of phosphaturic mesenchymal tumors delay the diagnosis? (2) What is the clinical course after surgical treatment of phosphaturic mesenchymal tumors? (3) How frequently do phosphaturic mesenchymal tumors recur and are there factors associated with recurrence?
  
  
  METHODS
  This study retrospectively reviewed the cases of five adults diagnosed and treated for phosphaturic mesenchymal tumors. Patients were identified through an internal orthopaedic oncology database with clinical, surgical, and histologic data obtained through a systematic chart review.
  
  
  RESULTS
  Five patients presented with a long-standing history of osteomalacia, generalized fatigue, pain, and weakness before the diagnosis was reached at an average of 7.2 years (range, 2-12 years) after initial symptom onset. The diagnosis appeared to be delayed owing to the cryptic medical presentation, difficulty in locating tumor by imaging, and confirming histologic appearance. Two patients treated with wide surgical resection did not experience recurrence compared with three patients who did show recurrent signs and symptoms after marginal excision. A postoperative increase in fibroblast-derived growth factor-23 was associated with recurrent disease.
  
  
  CONCLUSIONS
  Although uncommon, the diagnosis of phosphaturic mesenchymal tumor should be considered in any patient who presents with hypophosphaturic osteomalacia and no other physiologic cause. Definitive treatment is early, wide surgical resection.
authors.affiliation: Department of Orthopaedic Surgery, Duke University Medical Centerm, 200 Trent Drive, Box 2923, Durham, NC, 27710, USA, cameron.ledford@duke.edu.
authors.forename: Cameron K
authors.initials: CK
authors.lastname: Ledford
authors.forename: Nicole A
authors.initials: NA
authors.lastname: Zelenski
authors.forename: Diana M
authors.initials: DM
authors.lastname: Cardona
authors.forename: Brian E
authors.initials: BE
authors.lastname: Brigman
authors.forename: William C
authors.initials: WC
authors.lastname: Eward
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood / Q000652:urine; D057210:Delayed Diagnosis; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood; D006801:Humans; D017674:Hypophosphatemia / Q000175:diagnosis / Q000209:etiology*; D008297:Male; D008637:Mesenchymoma / Q000097:blood / Q000150:complications / Q000175:diagnosis* / Q000601:surgery*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009372:Neoplasms, Connective Tissue / Q000175:diagnosis / Q000209:etiology*; D010018:Osteomalacia; D010257:Paraneoplastic Syndromes / Q000175:diagnosis / Q000209:etiology*; D010710:Phosphates / Q000097:blood / Q000652:urine; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D061665:Time-to-Treatment; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D010710:Phosphates; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23