Clinical Report: Ependymomas in the Posterior Fossa: An In-Depth Analysis

Background

Ependymomas are rare central nervous system tumors, particularly in children, where they account for about 5% of pediatric CNS tumors. The posterior fossa is a common site for these tumors, and nearly 45% of affected children experience recurrence, complicating treatment.

Data Highlights

Recent studies indicate that the incidence of ependymomas in children is approximately 0.5 to 1.5 cases per 100,000 children per year. The median age at diagnosis for posterior fossa ependymomas is around 5 years, with a slight male predominance. Survival rates vary significantly based on molecular subtype, with PFA tumors showing a 5-year survival rate of approximately 50%, while PFB tumors have a 5-year survival rate exceeding 80%.

Key Findings

• Ependymomas are classified into two main molecular subgroups: PFA and PFB, which have distinct biological and clinical features.

• PFA tumors are associated with poorer clinical outcomes and are more common in younger children, with a median age of 5 years.

• PFB tumors typically present in adolescents and adults and exhibit a less aggressive clinical course.

• Epigenetic changes, such as H3K27me3 loss, are significant in PFA tumors and serve as important diagnostic markers.

• 1q gain and/or 6q loss in PFA tumors indicate a very high-risk subset linked to recurrence and poor survival.

• MRI is the primary imaging modality for assessing PFE, with distinct imaging phenotypes observed between PFA and PFB tumors.

Clinical Implications

Molecular classification of ependymomas is essential for risk stratification and treatment planning. Understanding the differences between PFA and PFB can guide clinicians in managing these tumors more effectively.

Conclusion

The integration of molecular profiling into the classification of posterior fossa ependymomas enhances prognostic accuracy and informs treatment strategies, ultimately aiming to improve clinical outcomes.

Related Resources & Content

1. Acta Neuropathologica, Current Perspectives on the Clinical Approach to Intracranial Ependymoma and Its Unique Molecular Subtypes, 2016 -- https://link.springer.com/article/10.1007/s00401-016-1643-0

2. Acta Neuropathologica, EZHIP: Advancing Insights into Pediatric Posterior Fossa Ependymoma, 2021 -- https://link.springer.com/article/10.1007/s00401-021-02382-4

3. Acta Neuropathologica, Neurofibromatosis Type 2 Increases Risk for Ependymomas with Diverse Locations, Histological Features, and Molecular Characteristics, 2021 -- https://link.springer.com/article/10.1007/s00401-021-02304-4

4. Journal of Neuro-Oncology, Tailored Treatment Strategies for Pediatric Ependymomas with Relapse or Refractoriness: Insights from a Single Institution Study, 2025 -- https://link.springer.com/article/10.1007/s11060-025-05004-1

5. Childhood Ependymoma Treatment (PDQ®) - NCI -- https://www.cancer.gov/types/brain/hp/child-ependymoma-treatment-pdq

6. Current Perspectives on the Clinical Approach to Intracranial Ependymoma and Its Unique Molecular Subtypes

7. EZHIP: Advancing Insights into Pediatric Posterior Fossa Ependymoma

8. Neurofibromatosis Type 2 Increases Risk for Ependymomas with Diverse Locations, Histological Features, and Molecular Characteristics

9. Tailored Treatment Strategies for Pediatric Ependymomas with Relapse or Refractoriness: Insights from a Single Institution Study

10. Childhood Ependymoma Treatment (PDQ®) - NCI

11. cancers Review H3K27me3 Loss in Central Nervous Sy

12. cIMPACT‐NOW update 11: Proposal on adaptation of diagnostic criteria for IDH‐ and H3‐wildtype diffuse high‐grade gliomas and for posterior fossa ependymal tumors - PMC

13. European standard clinical practice recommendations for newly diagnosed ependymoma of childhood and adolescence - ScienceDirect

14. European standard clinical practice recommendations for newly diagnosed ependymoma of childhood and adolescence

15. Phase 3 randomized trial of postirradiation chemotherapy in patients with newly diagnosed ependymoma: A report from the Children’s Oncology Group | Neuro-Oncology | Oxford Academic

16. ID #1021 Secondary analysis of outcome by treatment and age in ependymoma: A Report from the Children’s Oncology Group | Neuro-Oncology Pediatrics | Oxford Academic

17. Significant increase of high-risk chromosome 1q gain and 6q loss at recurrence in posterior fossa group A ependymoma: A multicenter study - PMC