A rare case of synchronous multicenter primary adenocarcinoma in the small intestine, cecal appendix and large intestine, in an 82-year-old man with a condition of acute abdominal inflammation, is reported. He underwent exploratory laparotomy, and a stenosing and infiltrative intestinal lesion was seen in the hepatic angle, along with multiple adherences between the loops of the small intestine. Right hemicolectomy was performed. The anatomopathological evaluation showed 12 foci of primary adenocarcinomas affecting the small intestine (eight foci), ileocecal valve, cecal appendix and large intestine (ascending and transverse colon).