Intracranial cholesteatomas of the type to which the name "pearly tumor" has often been applied comprise a distinctly rare group among tumors of the brain. Pathologic or clinical reports of these lesions are likely to find their way into medical literature for various reasons. In the epidermoid variety there is such a strikingly beautiful pearly luster that this, together with the rarity of such a growth, has often been deemed sufficient to warrant a report. From the year 1807, when Duméril1 first described one of these tumors, there have appeared at intervals further individual and collective reports of cases of the condition, together with intensive discussions both as to the origin of the tumor and as to the nomenclature. Some of the more important and complete descriptions are those of Johannes Müller2 in 1838, Virchow3 in 1855, Bostroem4 in 1897, Thomas5 in 1901 and Bailey