title: Spontaneous malignant transformation of conventional giant cell tumor.
abstract: Spontaneous malignant transformation of conventional giant cell tumor (GCT) of bone is exceedingly rare. We report on a case of GCT of the iliac crest in a 35-year-old woman with malignant change into a high-grade osteosarcoma 10 years after the first appearance of GCT on a radiograph. Since the patient refused therapy for personal reasons the tumor remained untreated until sarcomatous transformation occurred. Image cytometry showed DNA aneuploidy and a suspiciously high 2c deviation index (2cDI) in the primary bone lesion. A thorough review of the world literature revealed only seven fully documented cases of secondary malignant GCT which matched the definition of a "sarcomatous growth that occurs at the site of a previously documented benign giant cell tumor" and not treated by radiotherapy. These cases as well as the current one suggest that a spontaneous secondary malignant GCT presents as a frankly sarcomatous tumor in the form of an osteosarcoma or malignant fibrous histiocytoma. It usually appears at sites of typical GCTs-often without any recurrent intermediate state-and is diagnosed 3 or more years after the primary bone lesion. The prognosis is poor.
authors.affiliation: Institute of Cytopathology, Heinrich Heine University, Moorenstrasse 5, D-40225 Düsseldorf, Germany. grote@med.uni-duesseldorf.de
authors.forename: H J
authors.initials: HJ
authors.lastname: Grote
authors.forename: M
authors.initials: M
authors.lastname: Braun
authors.forename: T
authors.initials: T
authors.lastname: Kalinski
authors.forename: N
authors.initials: N
authors.lastname: Pomjanski
authors.forename: W
authors.initials: W
authors.lastname: Back
authors.forename: U
authors.initials: U
authors.lastname: Bleyl
authors.forename: A
authors.initials: A
authors.lastname: Böcking
authors.forename: A
authors.initials: A
authors.lastname: Roessner
mesh_terms: D000328:Adult; D001706:Biopsy; D001859:Bone Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D002471:Cell Transformation, Neoplastic / Q000473:pathology*; D005260:Female; D018212:Giant Cell Tumor of Bone / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D007085:Ilium / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging; D012516:Osteosarcoma / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D014057:Tomography, X-Ray Computed