title: Blister-like Aneurysms in Atypical Locations: A Single-Center Experience and Comprehensive Literature Review.
abstract: OBJECTIVE
  Blister-like aneurysms (BLAs) were originally described to arise typically along the nonbranching segment of the dorsal wall of the internal carotid artery (ICA); however, BLAs located in areas other than the dorsal ICA have been described more recently. We present a case series of "atypical" BLAs and a systematic review of the literature on this subject.
  
  
  METHODS
  We conducted a literature search using the key word "blister-like aneurysm." Studies reporting BLAs in locations other than the dorsal ICA wall were selected. Clinical presentation, treatment modality, complications, and outcomes (modified Rankin Scale for neurologic outcomes and Roy scale for radiologic outcomes) were extracted from each study. We also reviewed our single-institution experience with atypical BLAs and analyzed the topography and outcomes of all the atypical BLAs according to each specific treatment modality.
  
  
  RESULTS
  Atypical BLAs were observed in the anterior communicating, middle cerebral, basilar, posterior cerebral, anterior cerebral, and posterior inferior cerebellar arteries. Surgery was the treatment in 65% of patients, an endovascular approach was used in 30%, and a combined approach was used in 5%. A good outcome (modified Rankin Scale 0-1-2) was experienced by 88% and 55% of the patients in the endovascular and surgical groups, respectively. There were 4 deaths, 2 in the endovascular group and 2 in the surgical group.
  
  
  CONCLUSIONS
  Endovascular treatment of BLAs seems to be associated with reduced morbidity and mortality and to provide a better outcome compared with surgical approaches. Further prospective studies are needed to confirm these results. It is important for clinicians to remember that BLAs may also occur in sites other than the typical ICA location.
authors.affiliation: Division of Endovascular Neurosurgery/Interventional Neuroradiology, Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy. Electronic address: simone.peschillo@gmail.com.
authors.forename: Simone
authors.initials: S
authors.lastname: Peschillo
authors.affiliation: Division of Neurosurgery, Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Latina, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Miscusi
authors.affiliation: Division of Neurosurgery, Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Caporlingua
authors.affiliation: Division of Neurosurgery, Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors.forename: Delia
authors.initials: D
authors.lastname: Cannizzaro
authors.affiliation: Division of Neurosurgery, Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Santoro
authors.affiliation: Division of Neurosurgery, Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Delfini
authors.affiliation: Division of Interventional Neuroradiology, Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors.forename: Giulio
authors.initials: G
authors.lastname: Guidetti
authors.affiliation: Division of Neurosurgery, Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Missori
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
keywords: Blister-like aneurysm; Cerebral aneurysm; Endovascular treatment; Flow-diverter; Surgical treatment