Cortical ependymoma or monomorphous angiocentric glioma? 
Ependymoma is the third most common childhood intracranial tumor after medulloblastoma and pilocytic astrocytoma.  Most ependymomas occur in the posterior fossa and spinal cord but only five cases confined to the cerebral cortex have been reported.  The current case is a 5-year-old boy with a somewhat ill-defined cortical tumor diagnosed as pilocytic astrocytoma on biopsy, and treated with radiotherapy.  Nine years later, resection of the essentially unaltered tumor was performed for treatment of intractable seizures.  Histologically, the tumor had some areas with the typical appearance of ependymoma as well other areas which contained piloid cells.  There was also evidence of focal infiltrative growth.  These findings bore resemblance to a recently described entity monomorphous angiocentric glioma/angiocentric neuroepithelial tumor, which combines features of ependymoma with pilocytic and diffuse astrocytomas.  Both cortical ependymomas and angiocentric monomorphous glioma/angiocentric neuroepithelial tumor appear to be low-grade tumors although their rarity makes accurate prognosis problematic.  The current case has features of both entities, suggesting they may be closely related.