P.014 The natural history of third ventricle colloid cysts includes asymptomatic regression: a report of two cases and review of the literature

Abstract

Background: Colloid cysts of the third ventricle are a rare entity with an unclear natural history. Although intervening in the setting of a symptomatic patient is fairly straightforward, decision-making for asymptomatic patients is not. Few studies address this question and proposed risk factors for cyst progression vary.A cyst diameter exceeding 1 cm is a common indication for surgery. This is rooted in the belief that the natural history is continued growth. A few cases have recently surfaced that suggests some cysts may spontaneously regress without complication. We describe our experience with two such cases and contrast it with those of others. Methods: We collected all cases of “colloid cysts” identified as incidental findings on Brain CT scans in a large urban center with available follow-up. We then conducted a comprehensive review of the literature. Results: Among all incidental cases from our database, none required surgery and two were found to decrease in size on neuroimaging surveillance with interesting evolution in MRI signal characteristics. These cysts remain asymptomatic at last follow up. Conclusions: The natural history of colloid cysts includes spontaneous regression. This should be mentioned in counseling asymptomatic patients.