Histological examination showed, beneath a mild acanthotic and hyperkeratotic epidermis, there was a basophilic band in the upper dermis.

• 组织病理学检查见表皮角质层增厚,部分棘层轻度肥厚,真皮上部有呈水平方向的带状结缔组织区,轻度嗜碱性变;