Anal intra-epithelialneoplasia (AIN), provoked by HPV, is considered as an anal cancer precursor.Some articles noticed that it occurred among 11% and 52% of men who have sexwith men (MSM) infected with HIV and, among seronegatives, from 6% to 20% ofmen and from 1% to 2.8% of women. From 8.5% to 13% of high grade AIN will evolveto invasive carcinoma, needing follow-up and screening for prevention. Thereis no satisfactory treatment with low morbidity and recurrence is frequent.There are two main forms of treatment: topics (trichloroacetic acid, podophylin,podophylotoxin, imiquimod, photodynamic therapy) and ablatives (chirurgicalexcision, LASER, infrared, eletrocautery). Others consider acceptable an expectantmanagement. Topical therapy is justified because of multifocal presentationof HPV induced lesions and ablative treatments have similar incidences of morbidityand recurrence. Anyway, patients with histological abnormalities need suitablefollow-up, with anal Pap smears and high resolution anoscopy.
