title: Delayed radiation necrosis 7 years after gamma knife surgery for arteriovenous malformation--two case reports.
abstract: A 44-year-old woman and a 55-year-old woman were treated with gamma knife surgery (GKS) for occipital arteriovenous malformation (AVM). Angiography confirmed complete nidus obliterations 2 years after GKS. However, both patients complained of chronic headache and visual symptoms from around 7 years after GKS. Magnetic resonance imaging showed round masses with or without cystic change surrounded by large areas of brain edema. Angiography also showed complete obliteration of AVM at this time. Extended corticosteroid treatment failed to control the edema. Both patients underwent total surgical removal of the mass. Visual disturbance and chronic headache improved postoperatively and the brain edema rapidly subsided. The histological diagnosis was radiation necrosis in both cases, attributed to the low conformity index and large 12-Gy volume due to usage of a large collimator for GKS. These cases of delayed radiation necrosis after GKS suggest that surgical removal of necrotic lesions is necessary for radiation necrosis intractable to medical treatment.
authors.affiliation: Department of Neurosurgery, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan. tatsuki@m2.kufm.kagoshima-u.ac.jp
authors.forename: Tatsuki
authors.initials: T
authors.lastname: Oyoshi
authors.forename: Kazuho
authors.initials: K
authors.lastname: Hirahara
authors.forename: Koichi
authors.initials: K
authors.lastname: Uetsuhara
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Yatsushiro
authors.forename: Kazunori
authors.initials: K
authors.lastname: Arita
mesh_terms: D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000328:Adult; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D001163:Arteriovenous Anastomosis / Q000601:surgery*; D001929:Brain Edema / Q000188:drug therapy / Q000209:etiology / Q000473:pathology; D002536:Cerebral Arteries / Q000002:abnormalities / Q000000981:diagnostic imaging / Q000473:pathology; D002550:Cerebral Veins / Q000002:abnormalities / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006801:Humans; D007049:Iatrogenic Disease / Q000517:prevention & control; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009336:Necrosis / Q000209:etiology* / Q000473:pathology* / Q000601:surgery; D019635:Neurosurgical Procedures; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology*; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D011859:Radiography; D016634:Radiosurgery / Q000009:adverse effects* / Q000379:methods; D013995:Time; D016896:Treatment Outcome; D014786:Vision Disorders / Q000209:etiology / Q000473:pathology / Q000601:surgery; D014793:Visual Cortex / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology
chemical_list: D000305:Adrenal Cortex Hormones; D000893:Anti-Inflammatory Agents