High risk of acute deterioration in patients harboring symptomatic colloid cysts of the third ventricle.

OBJECT Patients harboring colloid cysts of the third ventricle can present with acute neurological deterioration, or the first indication of the lesion may appear when the patient suddenly dies. The risk of such an occurrence in a patient already identified as harboring a colloid cyst is unknown. The goal of this study was to estimate the risk of acute deterioration in patients with colloid cysts. METHODS A retrospective study was made of a cohort of patients with newly diagnosed colloid cysts who were recruited in The Netherlands between January 1, 1993, and December 31, 1997. Seventy-eight patients were identified, all of whom displayed symptoms. Twenty-five patients (32%) presented with symptoms of acute deterioration; four patients died suddenly and the cysts were discovered at autopsy. The overall mortality rate was 12%. Results of a multivariate logistic regression analysis demonstrated that no subgroup of patients presenting without acute deterioration could be identified on the basis of patient age, duration of symptoms, cyst size, or the presence of hydrocephalus. The national incidence of colloid cysts in The Netherlands is 1/10(6) person-years; the prevalence was estimated to be 1800 asymptomatic colloid cysts. CONCLUSIONS Acute deterioration was a frequent presentation among a national cohort of Dutch patients harboring symptomatic colloid cysts. The risk of acute deterioration in a symptomatic patient with a colloid cyst in The Netherlands is estimated to be 34%. The estimated risk for an asymptomatic patient with an incidental colloid cyst is significantly lower. These results strongly advocate the selection of surgical treatment for patients with symptomatic colloid cysts.