There is a lobulated mass within and expanding the fourth ventricle. The mass is isointense to the adjacent cerebellum on T1-weighted images and hyperintense on T2-weighted images. No evidence of hemorrhage or calcification is identified. After contrast infusion, vessels run through the mass with small, rounded, peripherally enhancing nodules within and just superior to the mass near the tectum. The cerebellum is effaced peripherally and the brainstem anteriorly. The mass extends anteriorly into the right foramen of Luschka as well as into the foramen of Magendie inferiorly, down to the upper cervical space dorsally.
A shunt catheter is seen in the right posterior parietal region coursing centrally with its tip just beyond the left leaflet of the cavum septum vergae. The lateral and third ventricles are dilated reflective of hydrocephalus.