Epidermoids tend to have a smooth grey surface and contain friable waxy material inside. It is different to a dermoid cyst in that it tends to connect to and envelop adjacent structures whereas dermoid structures usually have defined boundaries. Their presence can be ascertained 'outside' as a mobile, rubbery mass that presents as a cosmetic deformity.
Operative removal must be undertaken with care, as spillage of the tumour can occur which may lead to forms of meningitis or ventriculitis.
- Source: NeuroWiki.