Pagetoid dyskeratosis is a frequent incidental finding in hemorrhoidal disease

Background.-Pagetoid dyskeratosis is considered a selective keratinocytic r esponse in which a small part of the normal population of keratinocytes is induced to proliferate. Pagetoid dyskeratosis has been found incidentally i n the squamous epithelium of the skin in various locations and in the ectoc ervix in uterine prolapse. In cases in which these pale cells are conspicuo us, there is a hazard of overdiagnosis. It has been suggested that friction is the most probable inductor of the lesion. To the best of our knowledge, pagetoid cells have not been reported in surgically resected hemorrhoids. Objective and Design.-We here describe the location of pagetoid dyskeratosi s in the squamous epithelium of hemorrhoids and the incidence of this lesio n in a group of 100 unselected patients surgically treated for hemorrhoidal disease. In addition to the conventional histologic method, special staini ng procedures and an immunohistochemical study of cytokeratins were perform ed in selected cases. Results.-Pagetoid dyskeratosis was found in 68 cases (68%) and was a promin ent finding in 22 cases (22%). The cells of pagetoid dyskeratosis were stro ngly positive for high-molecular weight cytokeratin. These cells showed an immunohistochemical profile that was different from that of the surrounding squamous cells and indicative of premature keratinization. Conclusions.-In hemorrhoidal disease, the cushions are susceptible to traum a as a result of prolapse. In this setting, friction may be the stimulus fo r the appearance of pagetoid dyskeratotic cells. These cells must be distin guished from the artifactual clear cells of the squamous epithelium, glycog en-rich cells, and koilocytes. The lesion must also be distinguished from e xtramammary Paget disease, pagetoid spread of carcinoma cells, pagetoid Bow en disease, and pagetoid melanoma. Pathologists should be familiar with the histologic features of pagetoid dyskeratosis in hemorrhoidectomy specimens to avoid misdiagnosis. Routine histologic study is usually adequate for re cognizing this lesion.