Clinical presentation, imaging, and staging of anal cancer.

Perianal symptoms are common, and benign anorectal conditions have clinical features not too dissimilar to those associated with anal canal carcinoma. To avoid delayed diagnosis, physicians need to be cognizant of the possibility of anal canal carcinoma, which can be effectively treated with chemoradiation therapy without the need for mutilating surgery. Appropriate imaging studies should be obtained for accurate staging of the disease and for follow-up examinations after definitive treatment.