Acute hemorrhage in a colloid cyst of the third ventricle: A rare cause of sudden deterioration

BACKGROUND Acute neurological deterioration and death in a patient harboring a colloid cyst of the third ventricle remains a poorly understood phenomenon. Sudden neurological derangement caused by spontaneous bleeding within a colloid cyst is a rare and potentially fatal event, usually requiring immediate diagnosis and emergency surgical treatment. CASE DESCRIPTION A 47-year-old male presented with acute right-sided hemiparesis and speech impediment, followed by rapid deterioration of consciousness. Neuroimaging studies showed a rounded mass at the roof of the anterior third ventricle, causing biventricular hydrocephalus along with a left-sided basal ganglia hematoma. The lesion showed scattered foci of a recent hemorrhage which extended into the left lateral ventricle. Surgical treatment involved emergency external ventricular drainage followed by the prompt elective total resection of the lesion via a transcallosal route. Pathological findings confirmed the diagnosis of a colloid cyst with focal areas of vascular congestion and blood extravasation within its wall. CONCLUSIONS Spontaneous bleeding into a colloid cyst of the third ventricle may cause acute obstructive hydrocephalus and intracranial hypertension due to rapid enlargement of the lesion. This event may account for the sudden neurological deterioration and/or death observed in a previously asymptomatic patient. The diagnosis of hemorrhagic phenomena within a colloid cyst represents a challenge due to the variable signal usually displayed by these lesions on computed tomography (CT) and magnetic resonance imaging (MRI). Emergency ventricular drainage followed by elective tumoral removal constitutes a valid and safe treatment strategy.