[Early detection of anal intraepithelial neoplasia in high-risk patients]

The incidence of anal squamous cell carcinoma has increased alarmingly, particularly in high-risk groups such as men who have sex with men and immunosuppressed patients. Infection with an oncogenic strain of the human papillomavirus in the anal canal or perianal skin leads to anal intraepithelial neoplasias (AIN), progressive dysplastic intraepithelial lesions that are the precursors of anal squamous cell carcinoma. AIN can be diagnosed through cytological screening and biopsy guided by high-resolution anoscopy and can be treated using a range of procedures in an effort to prevent progression to invasive anal carcinoma. Given the recent advances in the understanding of this disease, and the increasing calls from experts for the establishment of screening programs to identify AIN, we review current knowledge on the condition, its diagnosis, and treatment from the point of view of dermatology.