title: Accessory middle cerebral artery associated with an unruptured aneurysm at its origin.
abstract: BACKGROUND
  An aneurysm originating from the junction of the A1 segment of the anterior cerebral artery and accessory middle cerebral artery (Acc-MCA) is markedly rare. We report a rare case of an Acc-MCA aneurysm, and discuss the clinical course and management of this rare condition.
  
  
  METHODS
  A 64-year-old man with a past history of cerebral infarction was revealed to have a left Acc-MCA and an aneurysm at its origin. The aneurysm was clipped via a transsylvian approach. Due to its location and projectile direction, the neck of the aneurysm was left partially unclipped.
  
  
  CONCLUSIONS
  Although an Acc-MCA aneurysm is very rare, it has a potential risk of rupture. Therefore, radical treatment is necessary for such aneurysms.
authors.affiliation: Department of Neurosurgery, Yokohama Sakae Kyosai Hospital, 132 Katsura-cho, Sakae-ku, Yokohama 247-8581, Japan.
authors.forename: Motohiro
authors.initials: M
authors.lastname: Nomura
authors.affiliation: Department of Neurosurgery, Yokohama Sakae Kyosai Hospital, 132 Katsura-cho, Sakae-ku, Yokohama 247-8581, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Tamase
authors.affiliation: Department of Neurosurgery, Yokohama Sakae Kyosai Hospital, 132 Katsura-cho, Sakae-ku, Yokohama 247-8581, Japan.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Kamide
authors.affiliation: Department of Neurosurgery, Yokohama Sakae Kyosai Hospital, 132 Katsura-cho, Sakae-ku, Yokohama 247-8581, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Mori
authors.affiliation: Department of Neurosurgery, Yokohama Sakae Kyosai Hospital, 132 Katsura-cho, Sakae-ku, Yokohama 247-8581, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Seki
authors.affiliation: Department of Neurosurgery, Yokohama Sakae Kyosai Hospital, 132 Katsura-cho, Sakae-ku, Yokohama 247-8581, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Iida
keywords: Accessory; aneurysm; anomaly; anterior cerebral artery; middle cerebral artery