title: Extraosseous osteosarcoma: single institutional experience in Korea.
abstract: OBJECTIVE
  Extraosseous osteosarcoma (EOO) is a rare soft tissue form of osteosarcoma without involvement of the skeletal system. Due to the rarity of disease, its clinical features and optimal treatment are yet to be defined.
  
  
  METHODS
  Between 1 January 1999 and 30 June 2008 ten patients were pathologically confirmed with extra-skeletal osteosarcoma. A retrospective analysis of the ten patients was performed.
  
  
  RESULTS
  The anatomical distribution of the osteosarcomas was as follows: lower extremities (n = 3), upper extremities (n = 2), breast (n = 2), lung (n = 1), cheek (n = 1) and retroperitoneum (n = 1). Nine patients initially underwent resection of the primary mass. One patient, who received six cycles of adjuvant doxorubicin and cisplatin chemotherapy was alive in remission at 42.6 months. One patient with postoperative radiotherapy after curative surgery was alive in remission at 6.2 months. However, all three patients who received curative resection but no postoperative radiotherapy or chemotherapy died of the disease at 10.7, 11.1 and 15.6 months after surgery. The median time to failure was only 4.4 months (95% CI, 0.6, 8.2 months) and the median survival time of all patients was only 11.1 months (95% CI, 5.6, 16.6 months). At the time of analysis, seven patients were dead and all died of the disease recurrence.
  
  
  CONCLUSIONS
  EOO should be treated as a soft tissue sarcoma with aggressive behavior and multimodality treatment should be actively sought to improve treatment outcome. The impact of adjuvant chemotherapy on survival of EOO needs further investigation.
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Soohyeon
authors.initials: S
authors.lastname: Lee
authors.forename: Mi Rae
authors.initials: MR
authors.lastname: Lee
authors.forename: Su Jin
authors.initials: SJ
authors.lastname: Lee
authors.forename: Hee Kyung
authors.initials: HK
authors.lastname: Ahn
authors.forename: Junho
authors.initials: J
authors.lastname: Yi
authors.forename: Seong Yoon
authors.initials: SY
authors.lastname: Yi
authors.forename: Sung Wook
authors.initials: SW
authors.lastname: Seo
authors.forename: Ki-Sun
authors.initials: KS
authors.lastname: Sung
authors.forename: Joon Oh
authors.initials: JO
authors.lastname: Park
authors.forename: Jeeyun
authors.initials: J
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000473:pathology / Q000628:therapy; D017024:Chemotherapy, Adjuvant; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007723:Korea; D008297:Male; D008875:Middle Aged; D012516:Osteosarcoma / Q000473:pathology / Q000628:therapy*; D011379:Prognosis; D012189:Retrospective Studies; D012983:Soft Tissue Neoplasms / Q000473:pathology / Q000628:therapy*; D016019:Survival Analysis; D016896:Treatment Outcome; D055815:Young Adult