The object of this paper is to emphasize the importance of sebaceous cyst among the precancerous lesions by a comparison of our group of cases with those reported by others. A review of the literature reveals that only Bishop1and Caylor2have reported anything of statistical nature. By sebaceous cyst we mean a retention cyst caused by the occlusion of one or more ducts of sebaceous glands with the accumulation of the secretion. Atheroma is a synonym for sebaceous cyst, but we prefer using the latter term, as we feel that it is more descriptive. In 1914 Ricker and Schwalbe3stated that reports of forty-three cases of malignant change in sebaceous cysts had been published up to that time. Seff and Berkowitz,4Busfield,5Narat6and others have subsequently reported similar cases, but none of these investigators has had a sufficient series to attempt statistical