The most common cause of ascending colon wall thickening is inflammatory disease, such as Crohn’s disease or ulcerative colitis. Patients need to undergo colonoscopy for a clear diagnosis and, if necessary, local pathology for biopsy. There is also the possibility of ascending colon tumor. Some broad-based tumors may also show up as localized colon wall thickening on imaging, and the test that can make a definite diagnosis is colonoscopy. Under the microscope, the location and size of the tumor can be generally observed, and pathological tissues of the tumor can also be taken to make a clear diagnosis.