Asymptomatic cysts of the pineal gland are found frequently by radiological examination of the brain or at postmortem examination. Symptomatic cysts are rare, and may require surgical intervention. Sudden death due to a cystic lesion of the pineal gland is very rare. A case of a 22 year old man who collapsed and died unexpectedly is reported. Postmortem examination revealed a glial cyst of the pineal gland and evidence of chronic obstructive hydrocephalus. Deaths from colloid cysts and pineal gland cysts are rare, but should be considered where no other cause of death is evident, especially with a history of headaches. Their small size, and their possible rupture on dissection can make them difficult to detect if a careful examination is not undertaken.