title: Chest wall secondary chondrosarcoma arising from enchondroma in a young Asian female.
abstract: BACKGROUND
  Enchondromas are benign tumours derived from cartilaginous tissue and they rarely undergo malignant transformation unless they occur in multiple sites such as in the case of Ollier disease.
  
  
  METHODS
  We report a rare case of a 36-year-old Chinese female, without any past medical history, who had a right chest wall tumour which was initially diagnosed to be benign, for which she was loss to follow up. The mass had been stable in size for the past 7 years until recently, when it gradually grew bigger. computed tomography (CT) scan of the thorax revealed that the mass had invaded the right chest wall suggestive of malignant change. She subsequently underwent an elective open right chest wall resection of the mass and chest wall reconstruction with mesh. A 3cm by 3cm tumour arising from the anterior aspect of the 4th rib was found intra-operatively. Post-operative course was uneventful. Histologically, the mass was confirmed to be chrondrosarcoma and resection margins were negative. The patient was discharged on 4th post-operative day and her latest CT thorax during follow up 2 years after operation did not show any tumour recurrence.
  
  
  CONCLUSIONS
  The aim of chest wall reconstruction is to avoid instability and prevent thoracic organs from being exposed if the defect size is ≥10cm or at least three ribs are resected. Polypropylene mesh may be relatively weak in terms of mechanical support for the chest wall, however, in this case, the defect is not too large and the laterally reflected pectoral muscle can provide enough support together with the mesh.
  
  
  CONCLUSIONS
  Secondary chondrosarcoma in a young Asian female arising from a benign solitary enchondroma in the absence of multiple enchondromatosis, such as Ollier disease or Maffucci syndrome, is extremely rare. Regular follow up including physical assessment and radiological imaging can result in earlier detection of malignant transformation obviating the need for aggressive surgical treatment involving multiple rib resections.
authors.affiliation: Department of Cardiac, Thoracic and Vascular Surgery, National University Hospital, Singapore. Electronic address: chihchiang.nieh@gmail.com.
authors.forename: Chih Chiang
authors.initials: CC
authors.lastname: Nieh
authors.affiliation: Department of Cardiac, Thoracic and Vascular Surgery, National University Hospital, Singapore.
authors.forename: Yang Chong
authors.initials: YC
authors.lastname: Chua
authors.affiliation: Department of Cardiac, Thoracic and Vascular Surgery, National University Hospital, Singapore.
authors.forename: Agasthian
authors.initials: A
authors.lastname: Thirugnanam
authors.affiliation: Department of Cardiac, Thoracic and Vascular Surgery, National University Hospital, Singapore.
authors.forename: Moe Htet
authors.initials: MH
authors.lastname: Hlwan
keywords: Asian; Case reports; Chondrosarcoma; Enchondroma; Female