Posterior Fossa Ependymoma, Group A (PFA)

**Semantic type:** Neoplastic Process

**Definition:** A circumscribed ependymoma that arises in the posterior fossa with characteristic DNA methylation patterns, including CpG island hypermethylation, global DNA hypomethylation, reduction of nuclear H3 p.K28me3 (K27me3) expression, and EZHIP overexpression. It usually occurs in children younger than five years. PFA ependymomas have a worst prognosis compared to PFB ependymomas.

**Synonyms:** - Group A Posterior Fossa Ependymoma - Group A Posterior Fossa Ependymoma, Pediatric-Type - Posterior Fossa Group A (PFA) Ependymoma - Posterior Fossa Group A (PFA) Ependymoma, Pediatric-Type - Posterior Fossa Group A Ependymoma