title: Clinical outcome for patients with dedifferentiated chondrosarcoma: a report of 9 cases at a single institute.
abstract: BACKGROUND
  Dedifferentiated chondrosarcomas consist of two distinguishable components: low-grade chondrosarcoma components and high-grade dedifferentiated components.
  
  
  METHODS
  Nine cases (4 males, 5 females) of dedifferentiated chondrosarcoma were treated in our institute. The average age was 58.6 (range, 37-86) years. The tumor location was the long bone in 7 cases (femur, n=5; humerus, n=1; tibia, n=1) and the pelvic bone in 2 cases. The average time from appearance of symptoms to treatment was 9.4 (range, 1-40) months.
  
  
  CONCLUSIONS
  On plain radiographs, matrix mineralization was seen in all 9 cases (100%). Bone destruction was observed in 5 of 9 cases (56%), while pathological fracture was seen in one femur case (11%). Lung metastasis was observed in all cases (initially in 5 cases; during the treatment course in 4 cases). Surgery was performed in 8 cases, with local recurrence occurring in 2 of those cases (time to recurrence, 2 and 10 months). Chemotherapy was administered in 4 cases, but did not result in significant improvement. All 9 cases died of lung metastases, with a median survival time of 10 (range, 3.4-18.8) months. The presence of initial metastasis at diagnosis was a significant unfavorable prognostic factor.
  
  
  CONCLUSIONS
  The prognosis of dedifferentiated chondrosarcoma is dismal. With the lack of convincing evidence of the benefit of chemotherapy, complete surgical excision is the initial recommended treatment.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Yokota
authors.forename: Akio
authors.initials: A
authors.lastname: Sakamoto
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Shuichi
authors.initials: S
authors.lastname: Matsuda
authors.forename: Katsumi
authors.initials: K
authors.lastname: Harimaya
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Oda
authors.forename: Yukihide
authors.initials: Y
authors.lastname: Iwamoto
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D054337:Cell Dedifferentiation / Q000502:physiology; D002813:Chondrosarcoma / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015996:Survival Rate / Q000639:trends; D016896:Treatment Outcome