Meningioma resembling an epidermoid tumor

A case of retro-orbital meningioma who presented to the Department of Surgery, Neuro-surgery Unit of Tikur Anbessa Hospital in June 1993 with a progressive right eye proptosis is described. Exploration through a right frontal craniotomy showed a well circumscribed and encapsulated thickened bony tumor that had a cavity containing a cheesy-yellowish oily material. The lesion was successfully shelled-out. The preoperative diagnosis was meningioma. However, based on its intraoperative macroscopic appearance, mode of presentation, and location of the lesion an impression of an epidermoid tumor (cholesteatoma) was made. The result of histologic examination turned out to be meningioma (psammomatous type). Literature review on both conditions, the pathologic characteristics and clinical features are discussed briefly.