Transethmoidal encephalocele after reduction of high intracranial pressure in aqueductal stenosis.

[hydrocephalus with stenosis of the aqueduct of sylvius]

Acquired non-traumatic transethmoidal encephaloceles are very infrequent lesions that are generally caused by a tumor or hydrocephalus . As far as we know , there is no reported case of encephalocele after CSF diversion in the literature . We present a 25 -year -old woman with hydrocephalus due to aquiductal stenosis who was treated with endoscopic third ventriculostomy . Nine months later , she had developed rhinorrhea and on imaging she had a transethmoidal encephalocele . She underwent endonasal endoscopic repair of the defect and removal of herniated parenchyma . CSF diversion to parasellar cisterns is not a known iatrogenic cause of basal encephalocele and is not noted elsewhere as a complication of third ventriculostomy . However , as third ventriculostomy is performed usually for intracranial hypertension treatment and intracranial hypertension itself is a known but rare cause of lacunar skull defect and encephalocele , this co -incidence may occur .