These relatively uncommon benign cysts or tumors arise from stratified squamous epithelium over the surface of the brain. The most common locations are around the brainstem, pituitary gland and in the posterior fossa along the cerebellum and brainstem. 

As the epithelial lining continues to produce the soft white keratin material, the cyst puts pressure on the adjacent brain structures and can cause headaches, weakness, imbalance, visual loss or seizures depending upon the cyst location. Some epidermoid cysts can rupture and result in a meningitis type reaction from inflammation.

These cystic tumors are typically diagnosed by magnetic resonance imaging (MRI) or computer tomography (CT) scans of the brain. Depending upon the location of an epidermoid cyst, a focused MRI of the pituitary region or internal auditory canals may be indicated to obtain better anatomical detail. 

Large epidermoid tumors causing symptoms are treated by surgical removal which is generally quite successful in resolving symptoms. Because the cyst lining can be very adherent to the brain structures a complete cyst removal may not be possible in many patients. If only a subtotal removal is accomplished, follow-up MRIs is necessary for many years to monitor for recurrence. Chemotherapy and radiotherapy are generally not used for treating epidermoid cysts.