A bulge in the descending colon with a rough surface is more likely to be malignant. A descending colon bulge is a pathologic manifestation of colonoscopy, and most are benign lesions, but regardless of whether they are benign or malignant, colonoscopic findings of a descending colon bulge require pathologic examination. Once the surface of the descending colon bulge is seen to be rough after colonoscopy and the tumor is large, it is more likely to be malignant and should be resected and pathologically examined at the location of the lesion under colonoscopy. If the tumor is relatively large and difficult to remove under colonoscopy, laparoscopic surgery or open surgery can be performed to remove it. It is recommended to go to the hospital for pathologic examination in time when the colon is bulging and the surface is rough. If the pathologic examination is malignant report, it is also necessary to judge whether to further chemotherapy and regular review. If the pathology report is benign, further treatment may not be needed, but regular review is also needed.