Malignant melanoma of the anal canal. Report of two cases.
D001005:Anus Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000601:surgery*; D005260:Female; D006801:Humans; D008545:Melanoma / Q000175:diagnosis / Q000453:epidemiology / Q000601:surgery*; D008875:Middle Aged; D012004:Rectal Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000601:surgery*