title: Giant cell-rich osteosarcoma in long bones: clinical, radiological and pathological features.
abstract: OBJECTIVE
  The purpose of this study was to review the clinical presentation, imaging, pathology and outcome of patients with giant cell-rich osteosarcoma (GCRO) of long bones.
  
  
  METHODS
  Radiography (n=9), magnetic resonance imaging (MRI) (n=6), computed tomography (CT) (n=3) and clinical course of nine patients (five males and four females; mean age, 26 years) with pathologically confirmed GCRO were retrospectively reviewed. Specific imaging findings, including size, eccentricity, ossification, lysis, cystic change, expansile growth, periosteal reaction, cortical destruction, soft tissue extension and joint involvement were documented.
  
  
  RESULTS
  Presenting symptoms were pain in six patients and pain and palpable mass in three. An ill-defined margin surrounding a predominantly osteolytic lesion was detected at the proximal tibia (n=7) or femur (n=2) on imaging studies. Seven cases showed limited ossification. Three cases had tumours in the metaphysis and six in the metaepiphysis. The average maximum tumour dimension was 4.7 cm×5.2 cm×7.8 cm. Microscopically, tumours were composed of atypical cells with scanty osteoid formation and multinucleated giant cells. All patients received chemotherapy, and surgery was performed in eight patients. Three patients were dead and six were alive at the last follow-up.
  
  
  CONCLUSIONS
  GCRO is a rarer variant that has very close resemblance to giant cell tumour. Patients usually present nonspecific symptoms of pain and palpable mass. It usually shows an osteolytic lesion with locally spared new bone formation in the metaphysis and/or metaepiphysis on imaging. Histologically, the atypical tumour cells with osteoid formation and multinucleated giant cells are the key factor in the diagnosis and differential diagnosis.
authors.affiliation: Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No.197, Ruijin 2nd Road, Shanghai, 200025, China.
authors.forename: Cheng-Sheng
authors.initials: CS
authors.lastname: Wang
authors.forename: Qi-Hua
authors.initials: QH
authors.lastname: Yin
authors.forename: Jin-Sheng
authors.initials: JS
authors.lastname: Liao
authors.forename: Jiang-Hua
authors.initials: JH
authors.lastname: Lou
authors.forename: Xiao-Yi
authors.initials: XY
authors.lastname: Ding
authors.forename: Yan-Bo
authors.initials: YB
authors.lastname: Zhu
mesh_terms: D000293:Adolescent; D000328:Adult; D003937:Diagnosis, Differential; D003952:Diagnostic Imaging; D005260:Female; D005266:Femoral Neoplasms / Q000175:diagnosis* / Q000473:pathology; D018212:Giant Cell Tumor of Bone / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012516:Osteosarcoma / Q000175:diagnosis* / Q000473:pathology; D012189:Retrospective Studies; D013977:Tibia / Q000473:pathology*