Primary epidermoid cysts of the temporal bone are very rare. Due to their slow growing nature, they may remain asymptomatic for many years. For treatment, complete removal is essential but is not easy due to complexity of the temporal bone air cells. We describe a 63-year-old female with a primary epidermoid cyst of the temporal bone. A female presented with mild dizziness and bilateral aural fullness was referred due to a tumor occupying the retrofacial air cells. On physical exam, she had normal tympanic membranes, facial and vestibular function. On pure tone audiogram, she shows mild sensorineural hearing loss and normal hearing on the right and left ears, respectively. On temporal bone CT, the tumor was located in the mastoid cavity and retrofacial air cells around the jugular bulb, which eroded the bony coverage on the posterior fossa dura and fallopian canal. Tumor was removed via extended mastoidectomy. During tumor removal, the tumor evaded the posterior fossa dura, so that it was torn and cerebrospinal fluid was leak. For dura repair, the Bioglue® was used. There was no recurrence 2 years after surgery.