Petrous Apex Epidermoid

Petrous apex epidermoid is a condition where skin gets entrapped into the petrous apex of the skull and forms a tumor.

Etiology for Petrous Apex Epidermoid

The entrapment of the skin in the petrous apex happens during development.   Skin is a very dynamic organ where the outermost layer is normally expelled.  In the petrous apex, this layer has nowhere to expel and continues to accumulate.  This causes remodeling of the bone within the petrous apex, and can also invade the facial nerve, inner ear, and brain.  The accumulation of skin can also cause infection.