Case report: The authors report two cases of arachnoid cysts (ACs) neither detected during pregnancy nor shortly after birth when newborns underwent CT scan evaluation after birth head trauma. ACs were diagnosed at 10 months and 6 years, respectively. The first one becomes symptomatic, and the other one was incidentally found during a head trauma investigation.
Discussion: These cases give support for the postnatal pathogenesis for some of the assumed congenital ACs. We collected data from the literature that supports the acquired hypothesis for ACs.
Keywords: Acquired; Congenital; Intracranial arachnoid cyst; Pathogenesis.