Ischemic colitis (IC) is an underreported chronic disease characterized by the hypoperfusion of the bowel mucosa. The diagnosis and treatment may be challenging because its clinical course resembles other colitis or even colorectal malignancies. This paper reports an untypical case to underline the diversity of IC manifestation. A 68-year-old man with several comorbidities was admitted because of abdominal pain with a 6-month duration and a mass in the left lower quadrant. Colonoscopy revealed erosive pseudomembranous colitis narrowed colon segments with ulcerated mucosa mimicking colorectal cancer and inflammatory bowel disease. The stool cultures and Clostridium difficile toxin tests were negative. After the failure of conservative therapy, the Hartmann procedure with temporary ileostomy was performed uneventfully. The histological results of the surgical specimens revealed IC with focal pseudomembranous areas.