see also Hemorrhagic colloid cyst of the third ventricle.
A case of a patient with a third ventricle colloid cyst in association with prepontine subarachnoid haemorrhage is presented. This was a 29-year-old healthy male who was admitted because of a depressed consciousness. Neuro-radiological imaging revealed a mass in the third ventricle, a biventricular hydrocephalus and a prepontine subarachnoid haemorrhage without any evidence of a cerebral aneurysm. Perimesencephalic nonaneurysmal subarachnoid haemorrhage is well known but its cause is still a matter of debate. A description is given of the association of this type of subarachnoid haemorrhage with an acute hydrocephalus caused by a third ventricle colloid cyst. Because of the potential morbidity and mortality of third ventricle colloid cysts, this association is described and should be considered as a rare presentation of third ventricle colloid cyst 1).