Disease characteristics and patterns of familial colloid cyst of the third ventricle: An international survey of the Colloid Cyst Survivors Group

Background: Colloid cysts of the third ventricle are rare benign tumors, accounting for approximately 1% of all intracranial tumors. Familial colloid cysts are less common, only 25 cases have been previously reported in the literature. We aim to describe demographic and disease-specific characteristics to reduce the knowledge gap with this potentially life-threatening tumor.Methods: We conducted a retrospective cohort study of 211 colloid cyst patients from the Colloid Cyst Survivors Group who completed a survey that included demographic and clinical data and inquired about family members diagnosed with a colloid cyst. Data was collected from October 14th, 2021 to October 27th, 2021. We compared our data with previously published cases from the literature.Results: A total of 211 responses from patients with a previous diagnosis of a colloid cyst completed our survey. 11.8 % were familial colloid cysts, of this group 60.8 % were symptomatic and 39.2 % incidental. We observed significant difference between symptom incidence between reports from the literature and our cohort: headache 75.5 % versus 49 % (p = 0.005); imbalance 13.2 % versus 31.4 % (p = 0.03); nausea 11.3 % versus 29.4 % (p = 0.02), and difficulty walking 1.9 % versus 19.6 % (p = 0.003). Additionally, we found first degree family member as the most frequent relative diagnosed with this disease.Conclusion: Our study involved the largest cohort of patients with familial colloid cysts. According to previous literature, siblings are the most prevalent family member affected by this disease, specifically among mono -zygotic twins. This suggests strong inheritance patterns and even genetic mechanism underlying the develop-ment of this disease.