Third Ventricular Subependymomas: Clinical Features and Outcomes over Two Decades

Introduction: Subependymomas are uncommon, benign slow growing CNS neoplasms that preferentially arise within the fourth and lateral ventricles. Rare case reports/series also mention third ventricle involvement. The aim of this study is to provide the first literature review on third ventricular subependymoma (TVSE) by compiling all reported cases over two decades and describing a case example.

Methods: The MEDLINE and EMBASE databases were searched for the publications between January 1, 2002, and January 1, 2022, using relevant MesH and non-MeSH terms, including “subependymoma,” and “third ventricle,” specifying those citations addressing human subjects. Methodology followed PRISMA guidelines.

Results: Of 788 identified studies, 11 met eligibility and were included in this study. The cohort consisted of 15 TVSE patients, including our case example. Adults were 80% with average age 35 ± 19 years, 67% were women. The mean age for the pediatric cohort was 5 ± 1 year, 67% were females. The most common presenting symptom in both cohorts was headache (80%), followed by memory disturbances (58%) in adults and vomiting (67%) in children. A craniotomy for tumor resection was performed in all symptomatic cases. Gross total resection (GTR) was performed in 67% of cases. The anterior interhemispheric transcallosal approach was the most commonly used (40%). Insertion of a ventriculoperitoneal shunt was required in 27% of cases. The cohort overall outcome showed improvement or no recurrence of disease in 70% of GTR patients. One patient expired peri-operatively.

Conclusion : Subependymoma must remain in the differential diagnosis for tumors of the third ventricle, albeit rare. TVSE’s clinical presentation mainly parallels hydrocephalus symptoms, hence awareness is of vital importance in order to treat such cases in a timely manner. Gross total resection should be the goal of surgery, as it can be curative and appears to give the most clinical improvement across the patient population.