Last edited 05/2019
The majority of cancers within the anal canal are squamous cell carcinomas. Normal skin lines the anus and rarely, basal cell carcinomas may arise in this area. Malignant melanomas can occur in the anal canal or the anus.
Anal carcinoma is uncommon.
It is usually infiltrative and ulcerating. Lymphatic spread is to groin lymph nodes. In extensive disease, spread may occur to para-aortic and iliac nodes.