An 84-year-old woman presented with anorexia. CT showed ascending colon and multiple liver tumors, and a colonoscopy showed severe stenosis due to a tumor in the ascending colon. We diagnosed obstructive colon cancer with multiple liver metastases. It was difficult to approach this case with a colonic stent, and we suggested a colostomy, but the patient strongly objected and requested to undergo resection; thus, a laparoscopic right hemicolectomy was performed. Intraoperatively, there was no normal liver tissue, and liver metastases were diffuse. Histopathologically, neuroendocrine carcinoma and differentiated tubular adenocarcinoma were found; MANEC was diagnosed. Oral intake was started on the third postoperative day, but liver failure progressed gradually. Despite the best supportive care and medication, the patient died of liver failure 16 days after surgery. We report our experience of a MANEC case with a poor prognosis along with a literature review.