title: Case Report of the positive exostosin-1 without B-cell lymphoma-2 gene expression of giant cell tumor lesion in hereditary multiple exostosis.
abstract: BACKGROUND
  The giant cell tumor, in which BCL-2 gene was expressed only in its malignant transformation, is a benign, primary skeletal neoplasm with variable biologic aggressiveness. The is of the giant cell tumor. A coexistence with hereditary multiple exostosis with expression of EXT-1 is very rare. The correlation between giant cell tumor in hereditary multiple exostosis is still not clearly determined.
  
  
  METHODS
  A 31-years-old female presented with pain and lump on her left wrist and a coexistence of non tender multiple lump in the right and left knee. A wide excision of the tumor and reconstruction using non vascularized fibular graft was performed, followed by histopathology and immunohistochemistry of EXT-1 and BCL-2.
  
  
  CONCLUSIONS
  In this case, the tumor showed negative BCL-2 and positive EXT-1 gene expression. Giant cell tumor and hereditary multiple exostosis also demonstrated associations of chromosomes 11 with a different pathological process.
  
  
  CONCLUSIONS
  Giant cell tumor in hereditary multiple exostosis revealed positive EXT-1 without BCL-2 expression. It still need more investigation to confirm the relationship between these tumors.
authors.affiliation: Orthopaedic Surgeon at Department of Orthopaedic and Traumatology, Medical Faculty, Udayana University, Sanglah General Hospital, Denpasar, Bali, Indonesia. Electronic address: ekawiratnaya@gmail.com.
authors.forename: I Gede
authors.initials: IG
authors.lastname: Eka Wiratnaya
authors.affiliation: Orthopaedic Resident at Department of Orthopaedic and Traumatology, Medical Faculty, Udayana University, Sanglah General Hospital, Denpasar, Bali, Indonesia.
authors.forename: Nyoman Gede
authors.initials: NG
authors.lastname: Aditya Gitapradita B
authors.affiliation: Orthopaedic Resident at Department of Orthopaedic and Traumatology, Medical Faculty, Udayana University, Sanglah General Hospital, Denpasar, Bali, Indonesia.
authors.forename: I G N
authors.initials: IGN
authors.lastname: Yudhi Setiawan
authors.affiliation: Chief of Orthopaedic and Traumatology Department at Sanglah General Hospital, Medical Faculty, Udayana University, Denpasar, Bali, Indonesia.
authors.forename: I Ketut
authors.initials: IK
authors.lastname: Suyasa
authors.affiliation: Professor at Orthopaedic and Traumatology Department at Sanglah General Hospital, Medical Faculty, Udayana University, Denpasar, Bali, Indonesia.
authors.forename: I Ketut
authors.initials: IK
authors.lastname: Siki Kawiyana
authors.affiliation: Professor at Orthopaedic and Traumatology Department at Sanglah General Hospital, Medical Faculty, Udayana University, Denpasar, Bali, Indonesia.
authors.forename: Putu
authors.initials: P
authors.lastname: Astawa
keywords: BCL-2 gene; Case report; EXT-1 gene; Giant cell tumor; Hereditary multiple exostosis