A TRANSPETROSAL APPROACH FOR EXTENSIVE EPIDERMOID CYST IN THE CEREBELLOPONTINE ANGLE IN A YOUNG ADULT

A 26-year-old male with a large epideroid cyst in the cerebellopontine angle (CPA) undergoing successful total removal via the transpetrosal approach is described. He was referred to our clinic with a history of left facial pain for five years and left hearing disturbance for three years. Computed tomography and magnetic resonance imaging revealed a low-density mass located at the left side of the brainstem, which extended from the ventral side of the medullae to the left parasellar region and medial temporal fossa without abnormal enhancement. Operation was performed via the transpetrosal approach under facial nerve electromyographic, somatosensory evoked potential and auditory brainstem response monitoring. Two-staged operation through the pre- and retrosigmoid route was performed and resulted in successful total removal. In such extensive epidermoid cysts as the present case, a wide operative field is required for total removal, so the transpetrosal approach is very useful