title: Osseous metastases of chordoma: imaging and clinical findings.
abstract: OBJECTIVE
  To describe the imaging and clinical characteristics of chordoma osseous metastases (COM).
  
  
  METHODS
  Our study was IRB approved and HIPAA compliant. A retrospective search of our pathology database for pathology-proven COM yielded 15 patients who had undergone MRI, CT, bone scan, and/or FDG-PET/CT. The imaging and clinical features of the COMs were recorded. A control group of age and gender matched chordoma patients without osseous metastasis was evaluated.
  
  
  RESULTS
  The COM mean maximal dimension was 6.4 ± 4.0 cm. The majority (60%) of patients had one lesion. Extra-osseous soft tissue component was present in 85% and was larger than intra-osseous component in 76%. On MRI the lesions were heterogeneous but predominantly T2 hyperintense with hypointense septae, and with variable enhancement. On CT the lesions were typically destructive or permeative; calcifications were rare. The extent of the soft tissue component was isodense to muscle on CT and therefore better evaluated on MRI. COM was in a body part contiguous to the site of the primary tumor. Compared to the controls, COM patients were more likely to have local recurrence (P = 0.0009) and positive resection margins (P = 0.002). At 1 year, 33% of COM patients were deceased and 13% had progressive metastases.
  
  
  CONCLUSIONS
  COM are associated with large extra-osseous soft tissue components, which are better visualized by MRI. They are often located in a body part contiguous to the site of the primary tumor, portend poor prognosis, and are associated with positive resection margins and local recurrence.
authors.affiliation: Division of Musculoskeletal Imaging and Intervention, Department of Radiology, Massachusetts General Hospital, 55 Fruit Street Yawkey 6E, Boston, MA, 02114, USA. cychang@mgh.harvard.edu.
authors.forename: Connie
authors.initials: C
authors.lastname: Chang
authors.affiliation: Department of Pathology, Massachusetts General Hospital, Boston, MA, USA.
authors.forename: Ivan
authors.initials: I
authors.lastname: Chebib
authors.affiliation: Division of Musculoskeletal Imaging and Intervention, Department of Radiology, Massachusetts General Hospital, 55 Fruit Street Yawkey 6E, Boston, MA, 02114, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Torriani
authors.affiliation: Division of Musculoskeletal Imaging and Intervention, Department of Radiology, Massachusetts General Hospital, 55 Fruit Street Yawkey 6E, Boston, MA, 02114, USA.
authors.forename: Miriam
authors.initials: M
authors.lastname: Bredella
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001859:Bone Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary*; D002817:Chordoma / Q000000981:diagnostic imaging* / Q000473:pathology*; D003287:Contrast Media; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals
keywords: Bone scan; CT; Chordoma; MRI; Osseous metastases; PET