title: [Clinicopathologic features of osteochondroma with malignant transformation].
abstract: OBJECTIVE
  To investigate the clinicopathologic, radiological and immunohistochemical characteristics of osteochondroma with malignant transformation.
  
  
  METHODS
  The clinical data, radiological imagings and hematoxylineosin stained histologic sections were reviewed in 463 cases of osteochondroma diagnosed in Shanghai 6th Hospital from 1991 to 2008, including 11 cases with malignant transformation. Immunohistochemical two-step staining was used to detect CK, vimentin, S-100 protein, p53 and c-myc expression in seven cases of osteochondroma with malignant transformation and 10 cases without malignant transformation. The relevant literature was reviewed.
  
  
  RESULTS
  Among the 11 cases with malignant transformation, five were single osteochondroma (5/408, 1.2%), and six were multiple osteochondromas (6/55, 10.9%). The male to female ratio was 10:1. These 11 cases were derived from femur (4 cases), tibia (3 cases), ilium (3 cases), shoulder bone (1 case) and pubis (1 case). There was one case that showed malignant transformation in both the femur and ilium. The mean ages for the malignant and non-malignant cases were 39.8 years and 20.4 years respectively. All the malignant cases showed large sized lesions with prominent calcification in the thick cartilage caps. The malignant component was low grade, peripheral chondrosarcoma (grade I-II). In some areas the tumor cells infiltrated the peripheral soft tissue and bone marrow. Of the seven cases with malignant transformation that had immunohistochemical staining, all were positive for vimentin and S-100 protein; p53 protein was positive in 2 of 7 cases.
  
  
  CONCLUSIONS
  Malignant transformation of osteochondroma was usually encountered in multiple lesions. Most patients were more than 30 years old with a long clinical history and with a male predominance. These tumors showed thick cartilage caps with prominent calcification. The lobulated nature of the tumors was evident and they infiltrated the surrounding soft tissue. The sarcomatoid component was peripheral type, well differentiated chondrosarcoma. p53 mutation may explain part of the molecular mechanism in the malignant transformation.
authors.affiliation: Department of Pathology, Shanghai 6th People's Hospital, Shanghai Jiaotong University, Shanghai 200233, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zheng
authors.forename: Hui-zhen
authors.initials: HZ
authors.lastname: Zhang
authors.forename: Jin
authors.initials: J
authors.lastname: Huang
authors.forename: Juan
authors.initials: J
authors.lastname: Tang
authors.forename: Liang
authors.initials: L
authors.lastname: Liu
authors.forename: Zhi-ming
authors.initials: ZM
authors.lastname: Jiang
mesh_terms: D000328:Adult; D000368:Aged; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D002471:Cell Transformation, Neoplastic / Q000473:pathology*; D002813:Chondrosarcoma / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D005097:Exostoses, Multiple Hereditary / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015831:Osteochondroma / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D011859:Radiography; D009418:S100 Proteins / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014746:Vimentin / Q000378:metabolism; D055815:Young Adult
chemical_list: D009418:S100 Proteins; D016159:Tumor Suppressor Protein p53; D014746:Vimentin