Anal Warts and DysplasiaAnal warts, anal dysplasia, and anal cancer are all caused by the human papilloma virus (HPV), a common virus that can be transmitted sexually. More 40 types of HPV can infect the genital and/or anal area. Some HPV types can cause warts; other HPV types can cause anal and cervical dysplasia and cancer. In women, warts can appear on and around the genitals and inside the vagina, on the cervix, and/or around the anus. Men typically develop warts on the penis, the testicles, and/or around the anus. Anal dysplasia is a pre-cancerous condition where the cells of the anal canal (lower rectum) undergo abnormal changes. Anal dysplasia can progress from low-grade (low risk) to high-grade (high risk) changes before it turns into cancer. This tumor usually develops slowly over a period of years. Anal cancer usually starts in the anal canal (lower rectum) or in the skin just outside of the anal canal opening.