What is a polyp? A polyp is any visible protrusion on the mucosa, regardless of size, shape, and tissue type, and is referred to as a polyp. The term polyp is now generally used for an elevated lesion above the mucosa that has not yet been histologically diagnosed. Classification and clinical manifestations of polyps According to the histological type of polyps, polyps are divided into two categories: neoplastic and nonneoplastic. 1, neoplastic polyps are adenomatous polyps of the large intestine, including: tubular adenoma, tubular villous adenoma and villous adenoma of the large intestine. Clinically, these three polyps are called neoplastic polyps or precancerous lesions. It is believed that part of colorectal cancer is malignant from adenoma, and the larger the polyp, the higher the malignancy rate. In particular, villous adenoma is most likely to become malignant, followed by tubular villous adenoma, and tubular adenoma is the least malignant. The malignancy rate of villous adenomas >2.0 cm is generally reported to be 50%. Clinical manifestations: The main manifestation of colorectal adenoma is bleeding. Long-term chronic bleeding in small amounts may lead to anemia, and in a few patients there may be large amounts of blood in the stool. This is followed by diarrhea, and in a few cases, colonic adenomas can cause intussusception, with symptoms of intestinal obstruction such as abdominal cramps and bloating. If the adenoma is located in the rectum, there may also be a feeling of rectal cramping and an increase in the number of stools. 2.Non-neoplastic polyps mainly refer to hyperplastic polyps, juvenile polyps, inflammatory polyps, mucosal hypertrophy redundancy, etc. It is generally believed that hyperplastic polyps do not become malignant; inflammatory polyps caused by ulcerative nodes and schistosomiasis can become malignant, while polyps caused by bacterial enteritis, allergic enteritis and amoebic enteritis do not become malignant. Clinical manifestations: mucosal hypertrophic polyps and hyperplastic polyps generally do not have clinical manifestations such as diarrhea and mucus and blood stools; inflammatory polyps may have clinical manifestations such as abdominal discomfort and mild diarrhea, and generally no obvious history of blood in stool.