Cerebellopontine Angle Epidermoid-MRI

This patient presented with left hemifacial spasm. Epidermoid cysts are congenital lesion caused by inclusion of ectodermal elements during neural tube closure, as opposed to dermoid cysts which have both epidermal and skin appendages such as hair and sebaceous cysts. Epidermoids are the 3rd most common cerebellopontine angle mass, after acoustic schwannomas and menigiomas. On imaging they are similar to arachnoid cysts but can usually be distinguished from them due to restriction on DWI and usually slight deviation from CSF on FLAIR.