title: Cavernous malformation of the optic pathway mimicking optic glioma: a case report.
abstract: OBJECTIVE
  Optic pathway cavernous malformations (CMs) are extremely rare, accounting for less than 1 % of all intracranial CMs. We report a case of optic pathway CM mimicking optic glioma because the initial magnetic resonance (MR) images did not disclose hemorrhagic findings such as popcorn-like lesion or hemosiderin ring.
  
  
  METHODS
  A 20-year-old woman presented with subacute left visual acuity loss and visual field defect and was referred to our hospital. Initial MR imaging findings were suggestive of optic glioma. Second MR imaging demonstrated hemorrhagic findings, but the hemorrhage was considered to be intratumoral hemorrhage from left optic pilocytic astrocytoma. She underwent radiochemotherapy and intravenous administration of corticosteroids but her symptoms deteriorated. Third and fourth MR imaging revealed enlargement of the hematoma. Therefore, the radiation therapy was interrupted at a delivered dose of 16.2 Gy, and craniotomy was performed to preserve residual right visual field. The lesion was totally removed and the histological diagnosis was CM. Her right visual field was preserved, but not improved.
  
  
  RESULTS
  The present case and previous cases suggest that optic pathway CMs sometimes do not initially manifest with signs of hemorrhage, so CMs should be included in the differential diagnosis of optic pathway lesions.
  
  
  CONCLUSIONS
  Histological confirmation with preparation for total resection should be considered for rapidly progressive cases even if the neuroimaging findings are compatible with optic glioma.
authors.affiliation: Department of Neurosurgery, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan.
authors.forename: Yui
authors.initials: Y
authors.lastname: Mano
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Kumabe
authors.forename: Ryuta
authors.initials: R
authors.lastname: Saito
authors.forename: Mika
authors.initials: M
authors.lastname: Watanabe
authors.forename: Teiji
authors.initials: T
authors.lastname: Tominaga
mesh_terms: D005260:Female; D020786:Hemangioma, Cavernous, Central Nervous System / Q000150:complications / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D020339:Optic Nerve Glioma / Q000503:physiopathology* / Q000601:surgery; D065866:Optic Tract / Q000473:pathology*; D014786:Vision Disorders / Q000209:etiology; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult