Sagittal T1 weighted MRI without contrast and axial T1 weighted MRI with contrast reveals an enhancing cerebellar mass in the midline and slightly to the left of midline. A mass arising in this location would be consistent with a medulloblastoma versus a solid astrocytoma. Note the mild enlargement of the temporal horns of the lateral ventricle consistent with early hydrocephalus secondary to 4th ventricular compression by the mass. Diagnosis: medulloblastoma