Ependymoma (WHO Grade 2–3)

Ependymomas are usually slow-growing tumors of the central nervous system that morphologically resemble the Ventricular system and the Spinal canal-lining Ependymal cells.

Epidemiology

According to the "Central Brain Tumor Registry of the United States," the annual incidence of ependymal tumors is approximately 0.43 patients per 100,000 inhabitants. Ependymomas account for approximately 1.8 % of all primary CNS tumors and approximately 6.8 % of all gliomas. In children and adolescents (0-19 years), ependymal tumors occur proportionally more frequently and account for approximately 5.2 % of all primary CNS tumors. Males are affected more frequently than females (1.3:1)[^2]. Although ependymomas preferentially occur during childhood and adolescence, they can occur at any age[^1].

Classification

According to the 2021 WHO CNS classification, supratentorial and infratentorial ependymomas are classified as WHO grade 2 or 3[^5].

Location

Two-thirds of ependymomas occur infratentorially in the 4th ventricle; the remaining third are located supratentorially, usually in the periventricular white matter. In contrast to a Medulloblastoma, which frequently arises from the roof of the 4th ventricle, an ependymoma often extends from the floor of the 4th ventricle.

Imaging

On imaging, ependymomas differ from medulloblastomas primarily by their frequent calcification, which occurs in fewer than 10 % of medulloblastoma cases[^2]. Ependymomas also frequently appear heterogeneous on T1-weighted sequences, and the exophytic component of ependymomas is often hyperintense on T2-weighted sequences[^2]. Ependymomas may show diffusion restriction on MRI, although this occurs significantly less frequently in ependymomas than in medulloblastomas[^4].

A possible, but not definitive, distinguishing feature between spinal ependymomas and astrocytomas is the presence of Syringohydromyelia in ependymomas, which occurs only very rarely in astrocytomas[^7].

Intramedullary Ependymomas

Ependymomas can occur along the entire spinal cord and are the most common gliomas of the caudal Spinal cord, Conus, and Filum. They are slow-growing tumors.

Surgical Videos

Spinal Metastases

The incidence of spinal metastases at the initial diagnosis of an ependymoma is approximately 5 %[^3].

Treatment Guidelines

The current guidelines and treatment recommendations for ependymomas can be found here: EANO Guidelines.