Case #56

CT

• Hyperattenuating solid mass centered in the fourth ventricle with internal foci of calcification and relatively hypoattenuating components
• Associated obstructive hydrocephalus with subependymal edema and supratentorial sulcal crowding
• Downward displacement of the cerebellar tonsils

MRI

• Heterogeneously enhancing mass centered in the fourth ventricle and bulging through the right foramen of Luschka measuring 4.8 x 3.7 x 4 cm
• The mass is isointense to slightly hyperintense to gray matter on T2 and demonstrates internal areas of more avid T2 signal hyperintensity
• Irregular internal areas of restricted diffusion
• Internal foci of susceptibility artifact corresponding with areas of calcification on the CT
• No substantial surrounding parenchymal edema
• Decreased ventricular volume status post placement of a ventriculostomy catheter terminating in the frontal horn of the right lateral ventricle