Intestinal tumors in dogs may have a low incidence, but they tend to have an infiltrative and quite aggressive behavior. Therefore, it is necessary to carry out good clinical staging for the best therapeutic and surgical planning. The patient, due to the aggressiveness of his neoplasm, underwent a very extensive surgical procedure. The neoplasm took over practically the entire perineal region, tail, anus and vagina. In this surgery a 10 cm margin of the rectum, a 3 cm lateral margin and the sentinel lymph node (iliac) were removed. After surgical recovery, all adjuvant therapy began, as well as postoperative chemotherapy.