The diagnosis of HPV warts is usually clinical. It can be conﬁrmed by whitening of the mucosa when acetic acid is applied. This can be done with and without magnification, including colposcopy and anoscopy. Cytologic examination is used for mucosal evaluation. 42 Perianal, anal and penile intraepithelial neoplasia classically present as a velvety erythematous plaque or as a hyperpigmented well-deﬁned plaque. A biopsy is helpful in establishing a diagnosis, particularly in verrucal lesions unresponsive to therapy or when warts have unusual features, such as hyperpigmentation, ulceration or excessive bleeding.