====== Intracranial arachnoid cyst classification ======

Intracranial [[arachnoid cyst]] can be classified as primary developmental cysts or secondary cysts. Primary cysts arise from the splitting of the [[arachnoid membranes]] in utero, resulting in the development of anomalous collections of cerebrospinal fluid (CSF). Secondary cysts are less common, often appearing after trauma, surgery, infection, or intracranial hemorrhage.

[[Pediatric Intracranial arachnoid cyst]]

===== Localization =====

Intracranial cysts are classified as supratentorial, infratentorial, and supra-infratentorial (tentorial notch)
((Candela S, Puerta P, Alamar M, Barcik U, Guillén A, Muchart J,
García-Fructuoso G, Ferrer-Rodríguez E. [Epidemiology and classification of
arachnoid cysts in children]. Neurocirugia (Astur). 2015 Sep-Oct;26(5):234-40.
doi: 10.1016/j.neucir.2015.02.007. Epub 2015 Apr 2. Spanish. PubMed PMID:
25843209.
)).

50-66% occurring within the middle cranial fossa in most series. Ten percent occur in the suprasellar and
quadrigeminal regions and approximately 5% each in the posterior fossa and over the frontal convexities.

==== Supratentorial arachnoid cyst ====

see [[Supratentorial arachnoid cyst]].

[[Ventricle Arachnoid Cyst]]

==== Infratentorial ====

see [[Posterior fossa arachnoid cyst]].