Treatment of disorder
Epidermoid tumor is a proinflammatory benign tumor developed from residual tissues of the embryonic period. Main body of this tumor is a membrane-like structure, and contains cornified material, keratin, in its inside. Growth of tumor is slow so that it gradually enlarged then compresses the brain. It is called as “Pearl tumor” since it looks gleaming white like pearl in surgical field. White cornified material can be removed by aspiration, but unless skim membrane is completely removed, it may recur. Tumor advances from cerebellopontine angle to opposite side, then advances and grows to chiasmal region through tentorial notch.
Regarding the image, its character is that of high signal is shown in diffusion weighed imaging DWI of MRI and displayed with white. Radiation therapy and chemotherapy with drugs are not effective, and removal by surgical operation is the basic treatment so that there are almost no epidermoid tumors which cannot be completely removed. Also, with the development of intraoperative neuro-monitoring (evoked potential measurement), risk for the nerve damage becomes lessor. However, in case when tumor rolled trochlear nerve underneath the Tentorial notch in, paying attention is requested and it is important to work for the preservation with having utmost attention.
25 cases of tumor at cerebellopontine angle region is judged as successful complete removal, but for 2 cases out of these 25 cases, tumor is reappeared and for these 2 cases, disorder symptoms are remained due to the abrasion with trochlear nerve.
Also, as for the specifics of the patient, that patient was complicated with high-frequent epilepsy. In the 29 self-experimental examples, half of 14 cases are forced to take epilepsy medicine after the surgery regardless the region of tumor, i.e. even with posterior cranial fossa.