An extra-axial, lobular, heterogeneous lesion in the posterior fossa with a dural attachment showing mixed solid, hemorrhagic, and cystic-like areas. The lesion erodes the internal skull table and invades the diploe, the straight sinus, the transverse sinus, the sigmoid sinus, and the jugular bulb on the right side. It causes displacement and compression of both cerebellar hemispheres and perilesional edema that partially obliterates the fourth ventricle and causes hydrocephalus; the lesion also extends to the supravermian cistern and displaces the midbrain rostrally.
On T1WI the lesion demonstrates a heterogeneous signal with a predominantly hypointense signal and small hyperintense foci.
On T2WI the lesion demonstrates a heterogeneous signal with a predominantly hyperintense signal, small hypointense foci, and internal flow voids.
On FLAIR the lesion demonstrates a heterogeneous signal with a predominantly hyperintense signal; we can depict the perilesional edema on cerebellar hemispheres and hydrocephalus with subependymal migration.
On SWI there is a susceptibility artifact and blooming due to a hemosiderin deposit; these areas show restricted diffusion seen as hyperintense areas on DWI and a loss of signal in the ADC map.
On T1WI + Gd there is a marked heterogeneous enhancement in solid regions, with a lack of enhancement in necrotic areas.