Clinical presentation of intracranial epidermoids: a surgical series of 20 initial and four recurred cases

Epidermoids are generally recognized as benign tumors; however, total resection is often difficult. The recurrence from the residual capsule, dissemination of the tumor, and aseptic meningitis are common problems. The aim of the present study was to analyze and report on the clinical characteristics of intracranial epidermoids, particularly complications and cases with a poor clinical outcome. 24 patients with intracranial epidermoids who were treated surgically at Tokyo Women's Medical University Hospital between 1997 and 2007 were examined. The location and size of the tumor, pre-and postoperative symptoms, adherence of the tumor to cranial nerves, and proliferative capacity were determined. The most frequent site of the tumor was the cerebello-pontine (C-P) angle (16/24); eight of these patients presented with hearing loss and six presented with trigeminal neuralgia. In many cases, hearing loss and diplopia persisted after surgery. All epidermoids located in the C-P angle were attached to and/or compressed the trigeminal nerves, therefore, the origin is suggested to be the dura mafer of petrous bone around the trigeminal nerve. Of all 24 patients, the tumor recurred in four (after 3, 5, 10 and 20 years). One patient had a poor prognosis, with dissemination and brain stem infarction. Epidermoids can recur from residual capsule adhering to the brain stem or cranial nerves up to 10-20 years after the initial surgery. Long-term follow-up imaging studies are required when complete resection of the tumor capsule is not possible. In rare cases, spontaneous cyst rupture, dissemination, and brain stem infarction result in a poor prognosis.