Epidermoid cyst traversing the pons into the fourth ventricle. Case report.

A rare case of epidermoid cyst traversing the brain stem is presented. Computed tomography revealed the mass within the fourth ventricle; magnetic resonance imaging showed the dumbbell-shaped mass extending from the prepontine cistern to the fourth ventricle. Despite the high mortality and morbidity of brain stem epidermoid cysts in the literature, the tumor was successfully removed. The advantages of magnetic resonance imaging over computed tomography are described.