title: [Multicentric giant cell tumor: clinical analysis of 9 cases].
abstract: OBJECTIVE
  To explore the clinical profiles, imaging features and prognosis of patient with multicentric giant cell tumor of bone (MGCT).
  
  
  METHODS
  Nine MGCT patients treated at our hospital between 1997 and 2010 were retrospectively examined. They had two or more separate lesions of giant cell tumor. There were 5 males and 4 females with an average age of 23 (14-37) years. Three patients (33%) were under 20 years old. There were 29 tumors in the series with an average of 3.2 (range, 2-10) per patient. Among 6 of them, a second lesion did not develop for >2 years after initial presentation. There were >2 sites of tumor involvement (n = 4) and 10 lesions (n = 1). Two patients had synchronous lesions involves 2 isolated locations. Twenty-nine lesions were located in spine, rib, femur, tibia, foot, hand, fibula and humerus. Three lesions of 2 patients involved metaphysic of long bones, one of whom was skeletally immature. All lesions had the typical histological features of giant cell tumor. The tumors were treated with curettage or resection was performed according to location and the Campanacci grade.
  
  
  RESULTS
  Twenty-two lesions underwent surgery in all 29 lesions of 9 patients. A total of 31 operations were performed. The average follow-up period was 6 (3-10) years.Four lesions of 2 patients had no recurrence during follow-up. Ten lesions (34%) relapsed in all 29 lesions and 4 operations were performed firstly at other hospitals.Seven patients had one or more recurrences with an average recurrence time of 2.5 years (range, 2 months-9 years).Six cases of local recurrence were within the first 2 years. Post-radiotherapy malignant transformation developed in 1 male patient with 10 lesions dying of malignant pulmonary metastasis. The total recurrence rate was similar to that of unifocal giant cell tumor.
  
  
  CONCLUSIONS
  MGCTs are likely to occur more in a younger population than unifocal giant cell tumors. And its risk of recurrence depends on the type of surgery.It is similar to the risk of recurrence for unifocal GCT. MGCT has vessel-axial distribution and multicentric generation. Long-term follow-up is necessary.
authors.affiliation: Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing 100044, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Li
authors.affiliation: Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing 100044, China. Email: bonetumor@163.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Guo
authors.affiliation: Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing 100044, China.
authors.forename: Rong-li
authors.initials: RL
authors.lastname: Yang
authors.affiliation: Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing 100044, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
mesh_terms: D000293:Adolescent; D000328:Adult; D001859:Bone Neoplasms / Q000473:pathology* / Q000601:surgery; D005260:Female; D018212:Giant Cell Tumor of Bone / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008297:Male; D009364:Neoplasm Recurrence, Local; D011379:Prognosis; D012189:Retrospective Studies; D055815:Young Adult