Report on a 12 years old patient with an arachnoid cyst of posterior cranial fossa and pseudotumor cerebri. This patient is a shunt dependent of his cyst-peritoneal shunt. This association and evolution of this pacient suggest a common and specifical pathogenic mechanism of these two pathologies based in a disturbance of the cerebral fluid circulation.
arachnoid cyst; pseudotumor cerebri; cerebrospinal fluid circulation