MRI features are of a large Galassi type III arachnoid cyst that fills the whole middle cranial fossa displacing the temporal, frontal and parietal lobe, with extension along the Sylvian fissure and communicates with subarachnoid space. It is important to note that the Galassi classification is not commonly used and it has a dubious clinical utility. 

Epidermoid cysts can sometimes mimic as arachnoid cysts, but they usually are partially or entirely not suppressed on FLAIR and show restricted diffusion on DWI. Epidermoid cysts also show a scalloped border that tends to insinuate into compartments and encase the vascular and neural structures.

It is hard to link the patient clinical symptoms directly to the presence of the arachnoid cyst.