TRICHILEMMAL CYST OF THE UPPER LIP

We report the apparent first case of a trichilemmal cyst presenting in traorally. Trichilemmal cysts are cysts of epithelial origin with a di stinctive keratinization pattern that simulates that of the human anag en hair follicle between bulge and sebaceous gland and in the sac surr ounding catagen hairs. This type of keratinization of outer root sheat h epithelium occurs when it is freed from its internal cover of inner root sheath. This particular case showed evidence of mild epithelial p roliferation and slight foci of ''metaplastic'' epidermoid keratinizat ion, possibly related to mild trauma. The rarity of intraoral hairs un doubtedly accounts for the lack of reported cases of trichilemmal cyst s in oral or perioral locations.