Primary adenocarcinoma of the appendix is an extraordinarily rare tumor, with fewer than 500 cases described in the collected world literature. However, it has been shown that the incidence of secondary neoplasm, such as synchronous or metachronous lesions, for primary adenocarcinoma of the appendix is much greater than that for colorectal cancer in general. In the present paper, the authors report a case of a 72-year-old male patient with immunoreactivity for P 53 and DCC protein and a review of the literature, who was operated on for an appendiceal orifice cancer and in whom colonic adenomas, a synchronous colon cancer and an appendiceal mucocele, was incidentally discovered after right hemicolectomy.