title: Giant distal anterior cerebral artery aneurysm not visualized on angiography: case report.
abstract: BACKGROUND
  Giant distal anterior cerebral artery (ACA) aneurysms are rare lesions, with only 10 cases having been reported in the literature. Their diagnosis may be difficult on computed tomography (CT) scan, often simulating a callosal tumor or hematoma, with only magnetic resonance imaging (MRI) scan or angiography allowing a correct diagnosis.
  
  
  METHODS
  The authors present one case of a giant distal ACA aneurysm not visualized on angiography, and whose MRI scan was interpreted as a hemorrhage from a cavernoma or a glioma. The correct diagnosis was only made during surgery, and was confirmed by histopathologic examination.
  
  
  CONCLUSIONS
  The authors conclude that distal ACA aneurysms must be considered in the presence of a callosal mass, even with negative angiography, especially if there has been evidence of bleeding from the lesion.
authors.affiliation: Department of Neurosurgery, Hospital de Santa Maria, Lisbon, Portugal.
authors.forename: J P
authors.initials: JP
authors.lastname: Farias
authors.forename: A M
authors.initials: AM
authors.lastname: Trindade
mesh_terms: D002343:Carotid Artery, Internal; D002533:Cerebral Angiography; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging*; D008875:Middle Aged; D014057:Tomography, X-Ray Computed