ABSTRACT
ETIOLOGY AND PATHOGENESIS Epidermal and follicular inclusion cysts are nonneoplastic swellings with an epithelial lining1,2. Epidermal inclusion cysts may result from the traumatic implantation of keratinaceous material of epidermal origin into the dermis. Follicular inclusion cysts may result from traumatic occlusion of the follicular canal, resulting in the accumulation of pilosebaceous material. Both are clinically indistinguishable from each other and from benign epidermal or follicular tumors.
