Possible causes of colonic bulging lesions include inflammatory polyps, colonic adenoma, colonic lymphoma, colonic cancer and so on. 1. Inflammatory polyp: Inflammatory polyp is a common bulging lesion of colon in clinic, which is an inflammatory hyperplasia formed by long-term chronic inflammatory reaction of colon mucosa, and generally has no tendency to become cancerous. 2. Colonic adenoma: colonic adenoma is a kind of benign tumor, but it has the tendency to become cancerous, and familial adenomatous polyposis is a kind of hereditary disease, which may develop into colon cancer if not treated in time. 3. Colon lymphoma: lymphoma is a malignant tumor originated from lymphatic tissues. As lymphatic tissues are spread all over the body, theoretically, lymphoma can occur everywhere in the body, while gastrointestinal tract is the most common site of extra-colonial lymphoma, and it can be manifested as bulging lesions under enteroscopy. 4. Colon cancer: some patients with colon cancer can show bulging lesions toward the intestinal lumen, which is called bulging colon cancer, and the surface can form erosions or ulcers. It originates from submucosal elevated lesions of the colon, such as cysts and GIST. It is recommended to go to the hospital as soon as possible to clarify the nature of the lesion and provide targeted treatment.