Anal Intraepithelial Neoplasia

**Semantic type:** Neoplastic Process

**Definition:** A precancerous neoplastic intraepithelial process involving either the squamous and transitional zones of the anal canal or the perianal skin (anal margin).

**Synonyms:** - AIN - Anal Canal and Anal Margin Squamous Intraepithelial Neoplasia - Anal Canal and Perianal Squamous Intraepithelial Neoplasia - Anal Dysplasia - Anal Squamous Dysplasia - Anal Squamous Intraepithelial Neoplasia - Intraepithelial Neoplasia of Anus - Intraepithelial Neoplasia of the Anus