Ruptured "giant" supratentorial dermoid cyst.

Intracranial dermoid and epidermoid cysts are rare lesions formed from the inclusion of ectodermal elements during neural tube closure. Although not entirely consistent, imaging characteristics on CT and MRI can aid differentiation of dermoids and epidermoids, as can age at presentation, location and tendency to rupture. The distinction between dermoid and epidermoid lesions is important prognostically and may impact on surgical management as a subtotally resected dermoid is less likely to recur than its epidermoid counterpart. The distinction of large dermoid lesions as "giant" adds little to information regarding the natural history or prognosis of these lesions and should be abandoned.