Histologically, LPR demonstrates a hyperplastic epidermis with striking colonization by atypical lymphocytes, especially in the lower reaches (Fig. 61.2). The lymphocytes are distributed singly, in small clusters or in large lacunae (Fig. 61.3). Involvement of adnexal epithelium is often a feature. The lymphocytes are medium to large, with hyperchromatic irregular nuclei and abundant vacuolated cytoplasm (Fig. 61.4). They usually have a perinuclear halo. Mitotic figures are sometimes conspicuous. The papillary and superficial dermis shows a mixed cell infiltrate with very sparse atypical cells.