Histopathologic examination showed hyperkeratosis of epidermis, increased thickness of the granular layer and dilation of subpapillary vessels filled with red blood cells.

组织病理学表皮角化过度,呈乳头瘤样增生,颗粒增厚,真皮乳头见大量增生扩张的毛,腔内含红胞,周围淋巴胞浸润。