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 monozygotic twins. This suggests strong inheritance patterns and even genetic mechanism underlying the development of this disease.