Recurrent posterior fossa anaplastic ependymoma with prominent chondroid metaplasia: a case report and review of literature.

We report an unusual case of a recurrent fourth ventricular anaplastic ependymoma with prominent chondroid metaplasia in a 16-year-old male. On initial presentation, the patient had a WHO Grade II tumor. However, at recurrence 1 year later, the tumor progressed to WHO Grade III tumor with more cellularity, necrosis and brisk mitotic activity. Chondroid metaplasia was present in both the initial and recurrent tumors.