title: Malignant Transformation of an Aneurysmal Bone Cyst to Fibroblastic Osteosarcoma.
abstract: Aneurysmal bone cysts are uncommon primary bone tumors typically regarded as histologically and clinically benign. Malignant transformation of these lesions occurs almost exclusively in the context of prior radiation exposure. However, 4 cases of an osteosarcoma developing without prior radiation exposure have been reported. In this article, we report a fifth case of degeneration of an aneurysmal bone cyst to a fibroblastic osteosarcoma. In addition to reviewing the earlier cases, we describe the radiologic, pathologic, and immunohistochemical basis of this diagnosis.
authors.forename: Akash P
authors.initials: AP
authors.lastname: Kansagra
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA. jennifer.wan@ucsf.edu.
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Wan
authors.forename: Kavi K
authors.initials: KK
authors.lastname: Devulapalli
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Horvai
authors.forename: Richard J
authors.initials: RJ
authors.lastname: O'Donnell
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Link
mesh_terms: D000328:Adult; D017824:Bone Cysts, Aneurysmal / Q000000981:diagnostic imaging / Q000473:pathology*; D002471:Cell Transformation, Neoplastic / Q000473:pathology*; D005264:Femoral Fractures / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology*; D005266:Femoral Neoplasms / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D008297:Male; D012516:Osteosarcoma / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology*; D014057:Tomography, X-Ray Computed