CHOLESTEATOMAS may be defined as globular masses composed of horny and desquamated epidermis and occasional cholesterol crystals surrounded by a thin shell of epidermis and connective tissue.1 While cholesteatomas do occur in other parts of the body, such as the calvaria,2 base of the brain, cerebellopontile angle, ventricles, choroid plexuses, and spinal column, the incidence in the middle ear and temporal bone is much greater. The rarity of cholesteatomas in other areas is attributed to the absence of statified, squamous epithelium. Moreover, it is assumed, in other instances, that their development stems from epithelial remnants deposited during embryonic life in some accident in the course of development. In these rare conditions the masses are called true cholesteatomas, in contradistinction to the cholesteatomas of the middle ear and temporal bone, which are of greater incidence and are termed pseudocholesteatomas. The latter, as will be brought out in the discussion