Hypertrophic actinic keratosis with adjacent (incidental) epidermodysplasia verruciformis

    Scaly papule on arm of 70 year old white male. The first image shows a hypertrophic actinic keratosis displaying a nice example of the "flag sign" (sharply alternating orthokeratosis and parakeratosis). Images 2-4 show an incidental finding in the skin immediately adjacent to the actinic keratosis. The blue-gray sqamous cells accompanied by hypergranulosis represent epidermodysplasia verruciformis due to infection with HPV types 5 and/or 8. This may rarely occur as a diffuse infection, but it is not uncommonly seen as an incidental finding in skin biopsy or excision specimens where it is thought to be of no clinical importance.