How was this patients obstructive hydrocephalus treated?
What does the mass most likely represent?
A large cavernous haemangioma.
What features a supportive of this diagnosis?
Complete peripheral hemosiderin ring with central heterogeneous signal. Blooming on gradient echo all supports the presence of significant blood products.
The ventricles have significantly reduced in size and the mass in the dorsal midbrain is still visible, again with peripheral hemosiderin and internal heterogeneous signal. There is no restricted diffusion. No surrounding oedema.
A prominent flow void is seen through the floor of the third ventricle in keeping with a third ventriculostomy. This is best seen on axial T2 images.