Intracerebral extension of nasal dermoid cyst: CT appearance.

We report on a 46-year-old man with a congenital nasal dermoid cyst that extended intracranially to form large bifrontal intraaxial dermoid cysts, which became secondarily infected through a nasal dermal sinus tract. Computed tomography demonstrated bilateral frontal lobe ring enhancing cystic masses containing fat-fluid levels consistent with dermoid cyst abscesses. Axial and coronal CT of the skull base and nose demonstrated a midline bony canal extending from two dimples on the dorsum of the patient's nose to the base of the anterior cranial fossa. The clinical, CT, and surgical findings are reviewed as well as the embryogenesis of congenital nasal dermoid cysts.