There is an extra-axial complex midline mass of retrocerebellar location, ruptured within the subarachnoid spaces and ventricular system. It appears of non-homogeneous high signal intensity on T1WI, T2WI, and FLAIR, with no enhancement following IV contrast and attenuated on suppressed fat sat sequence.
Dilatation of the ventricular system (3rd and lateral ventricles) with a fat-fluid level within the frontal horns as well as a "black boundary artifact". The fatty material appears hyperintense on T1WI, T2WI, and FLAIR, floating on the CSF and attenuated on the suppressed fat sequence. Small droplets of high signal intensity on T1WI, T2WI, and FLAIR attenuated on T2*, disseminated within the subarachnoid spaces (subarachnoid seeding), indicating an aseptic chemical meningitis.
Note small subcutaneous occipital tract sinus.