A child with a benign intrinsic tectal tumor and obstructive hydrocephalus developed
a huge intraventricular cystic lesion following insertion of a shunt, which was complicated
by a subdural-subarachnoid bleeding. The lesion was identified to be an entrapped
chiasmatic cistern, which disrupted the septum pellucidum in front of the third ventricle
and filled gradually the anterior horn of the lateral ventricle. The condition was
successfully treated endoscopically by fenestration of the cyst and a third ventriculostomy.
Probable mechanisms of such unusual cyst formation and general management strategies
in patients with obstructive hydrocephalus are discussed.
Arachnoid cyst - tectal tumors - obstructive hydrocephalus - neuroendoscopy