adenocarcinoid tumor is a rare malignancy that combines clinical and histological features of epithelial origin (adenocarcinoma) and neuroendocrine (carcinoid), occupies less than 1 % of all colorectal cancer histology, occurring mainly in the appendix and its presence in the colon is rare. we present a case of a 41-year-old female with sigmoid colon tumor, who underwent an extended left hemicolectomy and anastomosis; having a good postoperative evolution, with hospital stay of seventh days. The final histopathological study reported was adenocarcinoid colon tumor with free margins of injuries and four positive nodes of adenocarcinoma. adenocarcinoid tumors are present in the appendix in 85 to 95 % of all cases and only 6 % are located in the colon (13 % in sigmoid). Early diagnosis is certainly the most important determinant of good prognosis, in these cases the five-year survival is 80 to 84 %, and 15 years of 60 %.