Anal Dysplasia is a pre-cancerous condition associated with past or present exposure to Human Papillomavirus (HPV). It refers to abnormal changes in the cells that make up the lining (mucosa) of the anal canal. Abnormal cells clustered together form a visible pattern called a lesion. Low-grade lesions (LSIL) may progress to high-grade lesions (HSIL), which are more serious because they have the potential to progress to cancer in some people. Not all lesions progress to cancer and most of them won’t. Some may regress, meaning they shrink or even disappear. Some may persist, meaning they remain present without changing. The anus extends from the anal opening to about 1.5 inches inside the body to join the rectum. The portion inside the body is called the anal canal. Anal dysplasia occurs mainly in two places: at the "junction," where the anal canal meets the rectum or put another way, where the outside skin meets the inside rectal skin; and in the peri-anal skin, which is the skin just around the anal opening.