RESUMEN
Neuroendocrine tumor (NET) of the colon and rectum has been reported to have a low incidence and aggressive progression; it is frequently misdiagnosed and its treatment is not well documented. Four NET cases were collected at our hospital during the previous year of a colon cancer survey. Endoscopic mucosal biopsy of the colon was done for each case and all the cases proved to be adenocarcinomas. Curative surgery was conducted after the preoperative diagnostic and staging evaluation was completed. The locations of the primary lesions of the patients were all different; cecum, ascending colon, splenic flexure colon and sigmoid colon. The disease was advanced in all cases and the first postoperative diagnosis was poorly differentiated adenocarcinoma. Immunohistochemical tests followed and all the cases were positive for chromogranin A staining. A retrospective study was then conducted.