Beware frontotemporal dermoids - they may have intracranial extension: a case of a middle cranial fossa cyst.

Congenital orbitofacial dermoid cysts are epithelial lined structures of ectodermal origin that may be associated with sinus tracts and variable deep extension. Midline lesions may extend intracranially, while lateral lesions are thought never to do so. Consequently only midline lesions are usually imaged prior to surgery. We describe a lateral dermoid sinus communicating with an intracerebral dermoid cyst within the middle cranial fossa in a 3 year-old with recurrent periorbital cellulitis and intermittent discharge from a small pimple in the temporal region. This case demonstrates that some lateral "dermoids" need to be treated with more caution if there are unusual features such as dimpling, discharge of material or recurrent wider infection, and preoperative imaging should be carried out to exclude intracranial extension.