Anaplastic ependymomas (WHO grade III ependymomas), in comparison to lower grade ependymomas, are characterized by a higher proliferative rate and a greater tendency to infiltrate surrounding brain or disseminate into cerebrospinal fluid causing drop metastases . The relevance of grading ependymomas is questionable, though, and molecular subgroups are likely to carry greater importance .
About 25% of ependymomas exhibit features of anaplasia with a high mitotic rate, microvascular proliferation, cellular pleomorphism, and intratumoral necrosis; these are considered WHO grade lll .
These tumors have a greater propensity to infiltrate surrounding brain or spinal cord parenchyma and have a higher proliferative rate.
Anaplastic ependymomas have appearances that are similar to grade II ependymomas, although they may have a greater predilection for invading adjacent parenchyma .
Treatment and prognosis
The treatment and prognosis of ependymomas are not clearly influenced by histological grading .