epidermoid cyst - cerebellopontine angle

Role of

diffusion-weighted imaging in differentiation between posterior fossa brain tumors. Epidermoid cyst in 38-year-old male complaining from auditory problems. A lobulated extra-axial cystic lesion is seen in the right cerebellopontine angle (CPA) insinuating itself, compressing the pons, extending into prepontine cistern, and encasing the basilar artery. It displays low T1WI signal intensity (a) and high T2WI signal intensity cerebrospinal fluid (CSF) like (b). On FLAIR, it shows low SI (partially suppressed SI (c). It shows faint marginal enhancement on post-contrast study (d). It shows iso SI-like brain parenchyma (restricted diffusion); it does not have high CSF SI-like arachnoid cyst (e)