Natural History and Management Options of Colloid Cysts

Colloid cysts are benign epithelial lined cysts, and are generally located in the anterior third ventricle, in the region of the foramen of Monroe.1 They account for 0.5% to 2% of intracranial tumours 1,2 correlating to an incidence of 3.2 per million population per year.2,3 The true prevalence is unknown, but has been estimated at approximately 1 in 8500 people.4 Typical age of presentation is between 20 and 50 years, with a possible familial predisposition, 1 5,6 and a slight male preponderance.7
Prior to the availability of modern neuroimaging, most colloid cysts encountered in the clinical setting were symptomatic. With increased use of neuroradiology, asymptomatic colloid cysts are readily discovered following cranial imaging for unrelated indications. Symptomatic colloid cysts present with headache, which may be postural, associated with nausea and vomiting, blurred vision, gait ataxia, and altered cognition.2,8,9 Incontinence, tinnitus, seizures, syncope, psychological manifestations, and dizziness have also been reported.1,2 Because of their location (Figure 1), an enlarging cyst may cause obstructive hydrocephalus, resulting in acute rapid neurological deterioration and sudden death.