title: Spontaneous skull base meningoencephaloceles and cerebrospinal fluid fistulas.
abstract: Cerebrospinal fluid (CSF) fistulas are characterized by the egress of CSF from the intracranial cavity through an osteodural disruption between the subarachnoid space and a pneumatized structure within the skull base. Depending on the cause, CSF fistulas are classified as acquired or congenital, and acquired fistulas are further classified as traumatic, nontraumatic, or spontaneous. Spontaneous CSF fistulas are considered to result from a multifactorial process and have been postulated to represent a variant of idiopathic intracranial hypertension. However, an anatomic predisposition involving thinning of the cranial base, such as pneumatization of the sinus walls, must also be present. This process creates areas of structural weakness that act as potential pathways for CSF leaks, which most commonly occur in the ethmoid roof, sphenoid sinus, and temporal bone. Because CSF leaks may be overlooked, a result of their asymptomatic or subtle, intermittent course, a high level of suspicion is crucial in making an early diagnosis. However, CSF fistulas may be well seen at computed tomography (CT), which depicts bone defects, and magnetic resonance cisternography, which reveals the contents of herniated tissue. Knowledge of the location and size of the bone defect and herniated contents is crucial for the selection of surgical approach and grafting material.
authors.affiliation: Department of Diagnostic Imaging, Hospital Universitario Quirón Madrid, Calle Diego de Velázquez 1, 28223 Pozuelo de Alarcón, Madrid, Spain. rcanoalonso@gmail.com
authors.forename: Raquel Cano
authors.initials: RC
authors.lastname: Alonso
authors.forename: Mar Jimenez
authors.initials: MJ
authors.lastname: de la Peña
authors.forename: Anne Gomez
authors.initials: AG
authors.lastname: Caicoya
authors.forename: Manuel Recio
authors.initials: MR
authors.lastname: Rodriguez
authors.forename: Elena Alvarez
authors.initials: EA
authors.lastname: Moreno
authors.forename: Vicente Martinez
authors.initials: VM
authors.lastname: de Vega Fernandez
mesh_terms: D000328:Adult; D000368:Aged; D002559:Cerebrospinal Fluid Rhinorrhea / Q000150:complications / Q000175:diagnosis*; D004677:Encephalocele / Q000150:complications / Q000175:diagnosis*; D005260:Female; D005402:Fistula / Q000150:complications / Q000175:diagnosis*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008588:Meningocele / Q000150:complications / Q000175:diagnosis*; D008875:Middle Aged; D019291:Skull Base / Q000000981:diagnostic imaging* / Q000473:pathology*; D014057:Tomography, X-Ray Computed / Q000379:methods