title: The efficacy of resection of an intradural extramedullary foramen magnum cavernous malformation presenting with repeated subarachnoid hemorrhage: a case report.
abstract: BACKGROUND
  Intradural extramedullary cavernous angiomas of the central nervous system are a rare type of cavernous angioma, but they can cause fatal subarachnoid hemorrhage. The efficacy of resection for this type of cavernous malformations remains uncertain. This is the first report to recommend surgical resection of these types of lesions regardless of the fatal condition.
  
  
  METHODS
  Our patient was a 70-year-old Japanese man who experienced a sudden onset of an occipital headache, followed by bilateral abducens nerve palsy. Magnetic resonance imaging revealed a small amount of hemorrhage in both of the lateral ventricles and an intradural extramedullary mass lesion in the left side of his foramen magnum. Two weeks after the appearance of initial symptoms, he became comatose. A computed tomography scan showed an increase in the subarachnoid intraventricular hemorrhaging and of the acute hydrocephalus. Following ventricular drainage, total tumor resection was performed using the lateral suboccipital transcondylar approach in conjunction with a first cervical hemilaminectomy. We observed a grape-like vascular-rich tumor with calcification that was adhering tightly to the wall of his left vertebral artery. A histopathological examination of the surgery specimen identified it as a cavernous angioma. After placement of a ventriculoperitoneal shunt and 2 months of rehabilitation, he recovered completely.
  
  
  CONCLUSIONS
  An intradural extramedullary foramen magnum cavernous malformation is quite rare. The fragile surface of our patient's lesion was causing repeated subarachnoid hemorrhage and consequently progressive fatal neurological deterioration. Surgical resection of the lesion to prevent repeated hemorrhage was performed and he recovered fully. Therefore, we recommend surgical resection of the lesion regardless of the potentially fatal condition.
authors.affiliation: Department of Neurosurgery, Hamamatsu University School of Medicine, Handayama 1-20-1, Higashiku, Hamamatsu, Shizuoka, 431-3192, Japan.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Oishi
authors.affiliation: Department of Neurosurgery, Hamamatsu University School of Medicine, Handayama 1-20-1, Higashiku, Hamamatsu, Shizuoka, 431-3192, Japan. nsakaineurosurg@gmail.com.
authors.forename: Naoto
authors.identifier: http://orcid.org/0000-0001-7893-9323
authors.initials: N
authors.lastname: Sakai
authors.affiliation: Department of Neurosurgery, Hamamatsu University School of Medicine, Handayama 1-20-1, Higashiku, Hamamatsu, Shizuoka, 431-3192, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Sameshima
authors.affiliation: Department of Neurosurgery, Hamamatsu University School of Medicine, Handayama 1-20-1, Higashiku, Hamamatsu, Shizuoka, 431-3192, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawaji
authors.affiliation: Department of Neurosurgery, Hamamatsu University School of Medicine, Handayama 1-20-1, Higashiku, Hamamatsu, Shizuoka, 431-3192, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Namba
mesh_terms: D020434:Abducens Nerve Diseases / Q000209:etiology / Q000503:physiopathology*; D000368:Aged; D005539:Foramen Magnum / Q000473:pathology*; D006261:Headache / Q000209:etiology; D006392:Hemangioma, Cavernous / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000150:complications / Q000175:diagnosis* / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D013345:Subarachnoid Hemorrhage / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery; D016896:Treatment Outcome; D017287:Ventriculoperitoneal Shunt / Q000379:methods*
keywords: Abducens nerve palsy; Cavernous hemangioma; Craniocervical junction; Foramen magnum; Intradural extramedullary cavernous angioma; Subarachnoid hemorrhage