[Proliferating epidermal cysts]

While proliferating trichilemmal cysts are a well-known entity, so far there have been no reports on the proliferating processes of epidermal cysts. Two patients with multiple proliferating cysts are presented. Histologically, there was a well-developed stratum granulosum in the wall of the most cysts, and the cavity contained orthokeratotic horny material. The possible pathogenetic mechanisms of cyst formation are discussed.