Why is there a lump on the anus? The first thing you need to do is to get a good idea of what you are getting into. What’s wrong with a pimple in the anus? 1.Squamous cell carcinoma of anal canal: squamous cell carcinoma mostly occurs in the anal canal and around the anal canal. In the early stage, the skin around the anal canal and anus is thickened, or small nodular protrusions, followed by surface erosion and ulceration, with prominent edges, turning outward and surrounded by granular nodules. In the early stage, it is easily misdiagnosed as warts, thrombosed external hemorrhoids, etc., but biopsy can confirm the diagnosis. 2, malignant melanoma: malignant melanoma of the anorectum, originating from the malignant transformation of the melanocytes at the junction of the anorectum. The morphology is cauliflower-like or ulcerative in appearance, often with anal cramps, swelling, pain and other discomfort, and is easily misdiagnosed as hemorrhoids. Once diagnosed, radical surgery and regional lymph node dissection should be performed in a timely manner, along with immunotherapy to improve the efficacy. 3, hemorrhoids: internal hemorrhoid prolapse, annular mixed hemorrhoids, external hemorrhoid thrombosis, etc. when forceful defecation, a lump often appears outside the anus. 4, rectal prolapse: is a disease in which the anal canal, rectal mucosa or rectum and part of the sigmoid colon are displaced downward and prolapse outside the anus, commonly known as prolapse. The treatment of this disease is mainly to improve the weakness of qi and blood, get rid of diarrhea, constipation, long-term cough and other triggers. 5, rectal polyps: is a common benign tumor of the rectum, can be single or multiple, most polyps are round or oval masses with a tip, most commonly found in the lower rectum, when the bowel can be prolapsed outside the anus, after the bowel retraction. Adenomatous polyps are pre-cancerous lesions, which can become rectal cancer if treatment is delayed. 6, rectal cancer: 80% of the cases of delayed diagnosis of rectal cancer are due to the lack of rectal examination and mistaken for internal hemorrhoids because of blood in the stool. Correctly identify the characteristics of hemorrhoids and malignant tumors to avoid misdiagnosis and perform radical surgery early. 7, rectal smooth muscle sarcoma: rectal smooth muscle tumor is made by the proliferation of heterogeneous smooth muscle cells, mostly located in the lower rectum. The way it grows often protrudes into the rectal cavity, if not timely surgical treatment, it can turn from smooth muscle tumor into smooth muscle sarcoma, that is, from benign into malignant, resulting in rectal narrowing causing constipation, anal swelling and blood in the stool. The first thing we need to do is to confirm what the cause is, which requires us to go to the hospital for diagnosis, do not take it seriously, benefit early measures to avoid unnecessary harm.