Legend Left: Axial T2WI shows extraaxial heterogeneous posterior fossa mass splaying the cerebellar vermis with mass effect on the posterior medulla. Right: Sagittal T1WI shows T1 hypointense mass displacing the cerebellar vermis superiorly and occupying the inferior aspect of the 4th ventricle. The mass extends inferiorly below the foramen magnum. Hydrocephalus is manifested by decreased mamillo-pontine distance and dilated inferior recesses of the 3rd ventricle.

Legend Coronal and Axial post contrast T1WIs: The mass enhances intensely with mild heterogeneity. Key words: MRI tumor neoplasia intraventricular posterior fossa

Brain Diagnosis: Ependymoma