title: Dedifferentiated chordoma: a report of four cases arising 'de novo'.
abstract: Dedifferentiated chordoma is a rare and aggressive variant of the conventional tumour in which an area undergoes transformation to a high-grade lesion, typically fibrous histiocytoma, fibrosarcoma, and rarely, osteosarcoma or rhabdomyosarcoma. The dedifferentiated component dictates overall survival, with smaller areas of dedifferentiation carrying a more favourable prognosis. Although it is more commonly diagnosed in recurrences and following radiotherapy, there have been a few reports of spontaneous development. We describe four such cases, which were diagnosed de novo following primary excision, and discuss the associated clinical and radiological features.
authors.affiliation: Department of Orthopaedic Oncology, Royal National Orthopaedic Hospital, Stanmore, Middlesex HA74LP, UK. sammyhanna@hotmail.com
authors.forename: S A
authors.initials: SA
authors.lastname: Hanna
authors.forename: R
authors.initials: R
authors.lastname: Tirabosco
authors.forename: A
authors.initials: A
authors.lastname: Amin
authors.forename: R C
authors.initials: RC
authors.lastname: Pollock
authors.forename: J A
authors.initials: JA
authors.lastname: Skinner
authors.forename: S R
authors.initials: SR
authors.lastname: Cannon
authors.forename: A
authors.initials: A
authors.lastname: Saifuddin
authors.forename: T W R
authors.initials: TW
authors.lastname: Briggs
mesh_terms: D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000473:pathology* / Q000628:therapy; D002817:Chordoma / Q000473:pathology* / Q000556:secondary / Q000628:therapy; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged