(Multiple red-brown, pigmented papules or plaque on genital skin)

Microscopically, there were two distinct areas (Fig. 1.2). In one area, the epithelium was markedly hypertrophic with an overlying low papillomatous surface pattern while the adjacent epithelium was only slightly thickened compared to the surrounding epithelium. At higher magnification, there were additional distinctive features, the area that was less hypertrophic showed marked crowding of the keratinocytes with mitotic figures seen at all levels of the epithelium, while the thicker areas showed only a few mitotic figures with extensive koilocytic changes (keratinocytes with perinuclear clearing) at the upper layers of the epithelium (Figs. 1.3 and 1.4).