A Case of Synchronous Multiple Colorectal Cancer with Rectal Neuroendocrine Tumor and Ascending Colon Cancer

A 43-year-old man who had no previous medical history or family history had positive fecal occult blood test in a local physician. Colonoscopy revealed a type 2 tumor of the ascending colon and a 10 mm submucosal tumor(SMT)of the lower rectum. Biopsy indicated moderately-differentiated adenocarcinoma of the ascending colon and neuroendocrine tumor (NET)of the lower rectum. No metastasis was detected by computed tomography. Therefore, the rectal SMT was resected first by endoscopic submucosal resection. Histopathologically, the lesion was localized in the submucosa and no lymphovascular invasion was found. Vertical margin was also negative. We decided not to perform additional intestinal resection for rectal NET. Thereafter, the patient underwent laparoscopic right hemicolectomy for ascending colon cancer. The histopathological findings were pT3, pN1, pM0, pStage Ⅲb. The patient received adjuvant chemotherapy. No relapse was found 18 months after surgery. We reported a rare case of a lower rectal NET with concomitant ascending colon cancer.