Hemorrhagic colloid cyst: case report and review of the literature.

Colloid cysts are benign tumors situated in and connected to the roof of the third ventricle. The clinical presentation is diverse, varying from incidentally found cysts to acute death. This presentation is explained by an acute hydrocephalus due to an obstruction of the cerebrospinal fluid (CSF) flow at the level of the foramina of Monro. Why these lesions cause a sudden obstruction is not clear in most cases. Possible explanations of a sudden deterioration are shifts of the cysts after lumbar puncture or CSF flow obstruction after shunt dysfunction. We add an explanation for the acute deterioration of patients with colloid cysts (ie, hemorrhagic changes in the cysts). This complication has been published only 4 times before, all diagnosed at postmortem examination. A young patient is presented with a recently diagnosed and symptomatic colloid cyst who deteriorated the night before surgery because of intracystic hemorrhage. Despite emergent CSF diversion, our patient remained in a poor clinical condition. We review the literature about this topic and discuss the consequences for the neurosurgical practice.