title: Local recurrence of parosteal osteosarcoma adjacent to a prosthesis after 20 years: a case report.
abstract: We describe the treatment of an uncommonly late presentation of a recurrent parosteal osteosarcoma of the distal femur. The osteosarcoma had originally been detected 20 years earlier, and had been treated with wide excision and mega-prosthesis to reconstruct the femur. The tumour recurred in close proximity to the femur prosthesis and encased half the femoral stem. Because there was a large piece of metal at the site of recurrence, which might have interfered with computed tomography and magnetic resonance imaging, ultrasonography was used to locate the lesion. The tumour was successfully treated with wide local re-excision. This case emphasises the importance of the long-term follow-up of patients with parosteal osteosarcoma.
authors.affiliation: Department of Orthopaedics and Traumatology, The University of Hong Kong, Queen Mary Hospital, Hong Kong. catcherlau@hotmail.com
authors.forename: T W
authors.initials: TW
authors.lastname: Lau
authors.forename: J W K
authors.initials: JW
authors.lastname: Wong
authors.forename: D K H
authors.initials: DK
authors.lastname: Yip
authors.forename: E P
authors.initials: EP
authors.lastname: Chien
authors.forename: T W H
authors.initials: TW
authors.lastname: Shek
authors.forename: L L S
authors.initials: LL
authors.lastname: Wong
mesh_terms: D000328:Adult; D005260:Female; D005266:Femoral Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery*; D006801:Humans; D009364:Neoplasm Recurrence, Local; D012516:Osteosarcoma / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery*; D019736:Prostheses and Implants; D011859:Radiography