title: Diagnosis and treatment of low-grade osteosarcoma: experience with nine cases.
abstract: BACKGROUND
  Low-grade osteosarcoma, including low-grade central osteosarcoma and parosteal osteosarcoma, is an extremely rare variant, and the diagnosis is occasionally difficult. In this article we present cases of low-grade osteosarcomas that should be reviewed by a clinical oncologist.
  
  
  METHODS
  Nine cases of histologically diagnosed Broder grade 1 osteosarcoma were retrospectively reviewed. The pathological diagnoses included parosteal osteosarcoma, low-grade central osteosarcoma, and low-grade chondroblastic osteosarcoma in four, four, and one cases, respectively.
  
  
  RESULTS
  Duration from initial surgical intervention including biopsy to final diagnosis as low-grade osteosarcoma was a mean of 9.4 months. The initial benign diagnoses on biopsy specimens included fibrous dysplasia in three cases, chondroblastoma in one case, and a giant cell tumor in one case. The average number of histological examinations was 1.8. Low-grade osteosarcomas are well suited for biological reconstruction: seven cases were reconstructed by frozen autografts, distraction osteogenesis, or vascularized bone grafts.
  
  
  CONCLUSIONS
  Low-grade osteosarcomas can be misdiagnosed as benign lesions, especially fibrous dysplasia. If the diagnosis of a low-grade osteosarcoma is not established on the basis of radiologic findings, care should be exercised, even when a biopsy suggests a benign lesion. Low-grade osteosarcomas should be treated with wide excision, even after an intralesional excision. Biological reconstruction might be a better option for low-grade osteosarcomas.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan, hayashikatsu830@aol.com.
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Hayashi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsuchiya
authors.forename: Norio
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Shirai
authors.forename: Hideji
authors.initials: H
authors.lastname: Nishida
authors.forename: Akihiko
authors.initials: A
authors.lastname: Takeuchi
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kimura
authors.forename: Shinji
authors.initials: S
authors.lastname: Miwa
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Inatani
authors.forename: Hideki
authors.initials: H
authors.lastname: Okamoto
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yamada
authors.forename: Hiroko
authors.initials: H
authors.lastname: Ikeda
authors.forename: Seiko
authors.initials: S
authors.lastname: Sawada-Kitamura
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nojima
authors.forename: Akishi
authors.initials: A
authors.lastname: Ooi
authors.forename: Takanobu
authors.initials: T
authors.lastname: Otsuka
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000096:biosynthesis*; D001706:Biopsy; D001859:Bone Neoplasms / Q000175:diagnosis / Q000473:pathology; D051358:Cyclin-Dependent Kinase 4 / Q000096:biosynthesis; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D012516:Osteosarcoma / Q000175:diagnosis / Q000473:pathology; D051736:Proto-Oncogene Proteins c-mdm2 / Q000096:biosynthesis
chemical_list: D014408:Biomarkers, Tumor; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2; C495900:CDK4 protein, human; D051358:Cyclin-Dependent Kinase 4