ABSTRACT
In the United States, the incidence of squamous carcinoma of the anal canal and perianal skin in homosexual men has been estimated to be 11 to 34 times higher than the general male population. Perianal high-grade Anal Intraepithelial Neoplasia (AIN) can involve perianal skin, anal verge, anoderm, and vulvar. For an extensive involvement of the perianal skin, a circumferential excision should include the anoderm up to the dentate line because of its frequent involvement of the disease especially in Human immunodeficiency virus-positive patients. Squamous cell carcinomas of the perianal skin resemble those occurring in skin elsewhere in the body. There are only a few articles in the literature devoted to perianal squamous cell carcinoma, and it is five times less common than squamous cell carcinoma of the anal canal. AIN of the anal canal has been found in minor surgical specimens such as hemorrhoidectomy, as well as in females with vulvar and cervical neoplasm.
