title: Giant pseudoaneurysm in adolescent.
abstract: BACKGROUND
  Intracranial pseudoaneurysms, infrequent vascular lesion in children and adolescents, are characterized by the presence of organizing hematoma and fibrosis outside the true lumen instead of normal vascular elements. Because most pseudoaneurysms result from eminent insults such as major trauma or grave infection, development without preceding incident is extremely rare. Giant pseudoaneurysms in younger population, albeit unexceptionally unusual, are symptomatic in most instances and exhibit very high risk of rupture. Clinical manifestation as chronic headache without hemorrhage or neural compression is very unlikely. Once identified, only prompt surgical treatment guarantees favorable prognosis.
  
  
  METHODS
  We report a case of a 17-year-old boy with a giant pseudoaneurysm arising at distal middle cerebral artery. He complained of headache that had become apparent 3 years ago and medically intractable 3 months ago. Brain computed tomographic scan and lumbar cerebrospinal spinal fluid study revealed no trace of recent hemorrhage. However, digital subtraction angiography revealed a huge aneurysmal dilatation along the right distal middle cerebral artery with the features of delayed filling and emptying of contrast agent. Surgical obliteration of the corresponding aneurysm with tandem clipping and aneurysmectomy made him free of headache postoperatively.
  
  
  CONCLUSIONS
  We could not uncover the actual cause of formation and precise mechanism of clinical presentation for this unique aneurysm; nevertheless, we suggest that blunt head injury of fairly long history caused such a lesion, and repeated minute bleeding elicited headache. This assumption was possible only after full consideration of the histopathology.
authors.affiliation: Department of Neurosurgery, Hanyang University Medical Center, Sungdong-gu, 133-792 Seoul, South Korea. hjyi8499@hanyang.ac.kr
authors.forename: Hyeong-Joong
authors.initials: HJ
authors.lastname: Yi
authors.forename: Kwang-Myung
authors.initials: KM
authors.lastname: Kim
authors.forename: Yong
authors.initials: Y
authors.lastname: Ko
authors.forename: Young-Soo
authors.initials: YS
authors.lastname: Kim
authors.forename: Suck-Jun
authors.initials: SJ
authors.lastname: Oh
authors.forename: Seong-Hoon
authors.initials: SH
authors.lastname: Oh
mesh_terms: D000293:Adolescent; D017541:Aneurysm, False / Q000175:diagnosis / Q000473:pathology / Q000601:surgery; D002533:Cerebral Angiography / Q000379:methods; D006801:Humans; D002532:Intracranial Aneurysm; D008297:Male; D014057:Tomography, X-Ray Computed / Q000379:methods