Anaplastic Intraventricular Ependymoma

These images show a large lobulated enhancing partially cystic mass centered in the frontal horn of the left lateral ventricle with mass effect on the foramen of Monro resulting in obstructive hydrocephalus as evidenced by mild to moderate dilation of the supratentorial ventricular system and the thick rim of periventricular T2 FLAIR hyperintensity. The mass restricts diffusion compatible with hypercellularity. Differential considerations in this young patient include ependymoma, central neurocytoma, and choroid plexus lesions with meningioma, subependymoma, and metastasis considered less likely. Pathology revealed a high grade or anaplastic ependymoma. Approximately ⅓ of ependymomas are supratentorial and of these, less than half are intraventricular.