Four cases of neoplasms with mantle differentiation are presented. The mantle (sebaceous mantle) is a well-described but little known part of the sebaceous gland cycle. In the resting phase of that cycle, the mantle is seen as cords of undifferentiated cells that emanate from the infundibulum of a hair follicle and droop down aside the follicle in the form of a mantle or skirt. Cyclically, vacuolated sebocytes appear at the terminus of these cords, singly, then in groups, and finally as fully developed sebaceous lobules and glands. Presumably, sebaceous glands involute to become undifferentiated mantles. Clinically, neoplasms with mantle distribution occur on the face. Three of our cases were found fortuitously in sections of tissue removed because of basal-cell carcinoma. One was thought by the clinician to be a basal-cell carcinoma. Histopathologically, mantleomas vary in complexity. Presumably early neoplasms consist only of cords and columns of undifferentiated epithelial cells that radiate from an infundibulum. Later on, these cords interweave in a retiform pattern that contains sebocytes of varying degrees of vacuolization and sebaceous ductal structures. Mantleomas are benign because none in our series recurred after surgical removal and no atypical neoplastic cells were seen histopathologically.