[Anal and perianal tumors].

The anal canal extends from the anorectal ring to the anal verge. Different kinds of epithelium are existing. Below the dentate line is squamous epithelium, above columnar. In between is a gradual transition area, the so called transitional zone. According to the World Health Organization the anal margin is outside the anal verge and the anal canal reaches up to the superior border of the levator muscle. The lymphatic drainage of the anal margin is to the inguinal lymph nodes, from the anal canal to the inferior mesenteric nodes. Tumors of interest in the perianal location are Paget's disease and Bowen's disease as an intraepithelial adenocarcinoma or a squamous cell carcinoma in situ. Wide local excision is the treatment of choice. The true epidermoid carcinoma can be found at the anal margin and the anal canal. The symptoms are mild and unspecific. Many tumors are diagnosed late. The standard treatment has changed in the last 20 years. Local excision and abdominoperineal resections were followed by a high rate of local recurrence. The 5 year survival rate was 50% overall. The treatment of choice today is a combined chemoradiation therapy following Nigro's recommendation. The 5 year survival rate is approximately 85%.