Small bowel adenocarcinoma is a rare tumor, with a still not well studied tumorigenesis process, usually presenting in an advanced stage. The clinical diagnosis is often difficult; surgery is the treatment of choice when feasible, while the chemotherapeutic approach is still not well standardized. We describe the case of a 71-yr-old male patient, presenting with an acute right abdomen. At laparotomy the terminal ileum appeared chronically inflamed and thickened. An ileocecal resection with latero-lateral ileocolic anastomosis was performed. The gross appearance resembled an inflammatory bowel disease, but microscopic examination revealed the extensive presence of an infiltrating ileal adenocarcinoma. Literature about small bowel adenocarcinoma has been reviewed for better understanding its pathogenesis.