Four cases of neoplasms with mantle differentiation are presented. The
mantle (sebaceous mantle) is a well-described but little known part o
f the sebaceous gland cycle. In the resting phase of that cycle, the m
antle 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 a
s fully developed sebaceous lobules and glands. Presumably, sebaceous
glands involute to become undifferentiated mantles. Clinically, neopla
sms with mantle distribution occur on the face. Three of our cases wer
e found fortuitously in sections of tissue removed because of basal-ce
ll carcinoma. One was thought by the clinician to be a basal-cell carc
inoma. 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 co
rds interweave in a retiform pattern that contains sebocytes of varyin
g 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.