title: Radiation-induced osteosarcoma after Gamma Knife surgery for vestibular schwannoma: a case report and literature review.
abstract: We present a rare case of radiation-induced osteosarcoma following Gamma Knife®surgery (GKS) for a vestibular schwannoma (VS). A 49-year-old female with sporadic VS underwent GKS. Serial follow-up imaging showed that the tumor size decreased. Six years after GKS, magnetic resonance imaging demonstrated regrowth of the tumor. The tumor was removed via the retrosigmoid approach. Interestingly, the final pathology report confirmed osteosarcoma arising in schwannoma with direct transition (osteosarcoma component: 90 %, schwannoma component: 10 %). The osteosarcoma was considered to be a radiation-induced malignancy. The possibility of this rare complication should be explained to the patient before GKS, and the patient should be screened periodically after GKS.
authors.affiliation: Department of Neurosurgery, Seoul National University Hospital, Seoul National University College of Medicine, 101 Daehak-ro Jongno-gu, Seoul, 110-744, Korea.
authors.forename: Young-Bem
authors.initials: YB
authors.lastname: Se
authors.affiliation: Department of Neurosurgery, Seoul National University Hospital, Seoul National University College of Medicine, 101 Daehak-ro Jongno-gu, Seoul, 110-744, Korea. gknife@snu.ac.kr.
authors.forename: Dong Gyu
authors.initials: DG
authors.lastname: Kim
authors.affiliation: Department of Pathology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Sung-Hye
authors.initials: SH
authors.lastname: Park
authors.affiliation: Department of Neurosurgery, Seoul National University Hospital, Seoul National University College of Medicine, 101 Daehak-ro Jongno-gu, Seoul, 110-744, Korea.
authors.forename: Hyun-Tai
authors.initials: HT
authors.lastname: Chung
mesh_terms: D001859:Bone Neoplasms / Q000000981:diagnostic imaging* / Q000209:etiology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009381:Neoplasms, Radiation-Induced / Q000000981:diagnostic imaging*; D009464:Neuroma, Acoustic / Q000532:radiotherapy*; D012516:Osteosarcoma / Q000000981:diagnostic imaging* / Q000209:etiology; D016634:Radiosurgery / Q000009:adverse effects*
keywords: Gamma Knife radiosurgery; Osteosarcoma; Radiation-induced sarcoma; Stereotactic radiosurgery; Vestibular schwannoma