title: Causes of arachnoid cyst development and expansion.
abstract: Arachnoid cysts are frequent incidental findings on neuroimaging studies and in clinical practice. Theories of their origin, still matter for debate, compose four categories: 1) a ball-valve mechanism; 2) an osmotic gradient between the intra- and extracystic medium; 3) primary malformation of the arachnoid membrane or cerebral lobe agenesis; and 4) fluid hypersecretion by the lining cells of the cyst wall. The cause of cyst enlargement is also debatable, although there is strong controversial evidence supporting the last two theories rather than the former. Brain water homeostasis and its regulatory pathways are weakly understood at the molecular level. In this brief report the authors attempt to add new insights into the pathogenesis of arachnoid cysts by considering aquaporin expression in the cyst wall and discuss possible future research directions and molecular targets.
authors.affiliation: Departments of Neurosurgery and Pathology, Treviso Regional Hospital, University of Padova, Italy. luca.basaldella@mac.com
authors.forename: Luca
authors.initials: L
authors.lastname: Basaldella
authors.forename: Enrico
authors.initials: E
authors.lastname: Orvieto
authors.forename: Angelo Paolo
authors.initials: AP
authors.lastname: Dei Tos
authors.forename: Mila
authors.initials: M
authors.lastname: Della Barbera
authors.forename: Marialuisa
authors.initials: M
authors.lastname: Valente
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Longatti
mesh_terms: D051398:Aquaporin 1 / Q000737:chemistry / Q000378:metabolism; D001099:Arachnoid / Q000002:abnormalities / Q000196:embryology; D016080:Arachnoid Cysts / Q000473:pathology* / Q000503:physiopathology*; D001921:Brain / Q000473:pathology; D006801:Humans; D008958:Models, Molecular
chemical_list: D051398:Aquaporin 1