Viral wart. Light micrograph of a section through a wart caused by a virus in a person's skin, showing the exophytic papillary form. The epidermis (dark pink) is irregularly thickened and covered by a layer of hyperkeratosis (red), in which there are parakeratotic spires (thin lines) over the tips of the papillary epidermal outgrowths. The dermis (light pink, bottom) shows chronic infiltration of inflammatory cells.