A 75-year-old woman presented with a 1-month history of right lower quadrant pain and constipation. Physical examination revealed tenderness to palpation. The patient had no history of inflammatory bowel disease. The colonoscopy displayed marked partial obstruction of the cecum with a large ulcerated area and surrounding friable epithelium in the medial cecal region. Microscopic evaluation of the biopsy specimens revealed an acute ulcer with granulation tissue and overlying fibrinopurulent debris. There was no evidence of granulomatous inflammation or crypt abscesses suggesting inflammatory bowel diseases, except the atypical epithelial cells. Additionally, abdominopelvic tomography showed a suspicious cecal tumor underlying a thickened bowel wall and mesocolic lymph adenopathy. Subsequently, we performed right hemicolectomy due to clinical obstruction. No complications were observed during postoperative follow-up. The pathology result confirmed cecal ulcer with low-grade dysplasia