(1) Blood in stool: It often appears as blood on the surface of stool, bright red or dark red in color, and the amount of blood is not necessarily large, so it is easily confused with bleeding from internal hemorrhoids or rectal polyps. (2) Anal pain: The anal canal and perianal nerves are sensitive, so pain may appear at the early stage of the tumor, and the pain is aggravated when defecating. It is easily misdiagnosed as perianal abscess or hemorrhoid. (3) Prolapse of intra-anal swelling or perianal swelling: The swelling in the rectum of the anal canal prolapses outside the anus. Some of them prolapse during stool and can be incorporated into the anus on their own after stool; others cannot be incorporated after stool or the swelling at the edge of the anus bulges, sometimes accompanied by ulcers. Many people will treat it as hemorrhoids. (4) Change in stool habits: Increased frequency of stools, thinning, and a feeling of swollen stools in the anus. Because of the superficial location of anal canal and perianal malignant tumor, anal finger examination and anoscopy can make preliminary diagnosis and differentiation, and tissue biopsy can confirm early diagnosis when malignant tumor is suspected. Therefore, if symptoms such as blood in stool, anal pain, anal swelling and abnormal stool occur, you should come to anorectal specialist for examination as early as possible to avoid missing the best time for treatment.