Hemorrhagic colloid cyst with sudden coma.

Background: Third ventricle colloid cysts are regarded as benign lesions. They may, however, present with dramatic and rapidly deteriorating neurological signs, leading to sudden death. Although the exact cause of this clinical course is unknown, acute hydrocephalus caused by occlusion of Monro's foramina has been suggested. This, in turn, may be the result of acute cyst swelling, which can exceptionally be due to an intralesional hemorrhage.

Case report: This report illustrates the case of a young patient who deteriorated to sudden coma and was found to have a hemorrhagic colloid cyst of the third ventricle. This was removed via a purely endoscopic technique. Although the radiological results were excellent, the clinical outcome was poor.

Conclusions: This case suggests once again the importance of the early recognition of colloid cysts of the third ventricle for appropriate treatment before potentially irreversible neurological deterioration sets in.