Verrucous cyst.

Human papillomavirus has been detected in a variety of cutaneous premalignant and malignant conditions, as well as in benign cutaneous warts. Changes consistent with epidermis papilloma virus infection occurring in epidermal cysts have recently been reported in the dermatologic literature only in plantar epidermal cysts. We report five examples of a form of cutaneous cyst that is histologically distinctive and that has not been previously reported, to our knowledge. We describe five cases of epidermal cysts showing marked verrucous changes of their stratified squamous inner linings, some of which also show proliferative changes. Human papillomavirus genomes were detected via polymerase chain reaction. None of the DNA probes for Southern blot hybridization demonstrated homology with the human papillomavirus types usually associated with cutaneous warts or carcinoma. We believe this cyst to represent a newly described manifestation of human papillomavirus infection, and propose the name verrucous cyst for this entity. Further studies may reveal the specific human papillomavirus type(s) associated with the verrucous cyst.