title: Huge arachnoid cyst incorporating choroid plexus.
abstract: BACKGROUND
  We report a rare case of arachnoid cyst incorporating choroid plexus. This 7-month-old girl presented with macrocrania. Magnetic resonance (MR) imaging disclosed a cystic lesion arising from the left prepontine cistern extending to the left middle cranial fossa.
  
  
  METHODS
  First, we performed resection of the membrane microscopically and obtained an adequate reduction of the cystic size. However, 4 months after the first operation, the cyst was enlarged again, and bulging of the portion of the craniotomy was noted. Thus, we performed neuroendoscopic transcortical ventriculo-cyst-cysternostomy and confirmed the choroid plexus inside of the arachnoid cyst.
  
  
  CONCLUSIONS
  Postoperative course was uneventful. This is the first reported case of choroid plexus within an arachnoid cyst, determined neuroendoscopically.
authors.affiliation: Division of Pediatric Neurosurgery, Jikei Women's and Children's Medical Center, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Tokyo 105-8461, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Hamada
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Nonaka
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Kusaka
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Nakazaki
authors.forename: Saad Hamdan
authors.initials: SH
authors.lastname: Abdullah
authors.forename: Shizuo
authors.initials: S
authors.lastname: Oi
mesh_terms: D016080:Arachnoid Cysts / Q000150:complications / Q000473:pathology* / Q000601:surgery; D002831:Choroid Plexus / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D044583:Neuroendoscopy; D012086:Reoperation; D012886:Skull / Q000002:abnormalities*; D016896:Treatment Outcome