Clinically detected neuroendocrine neoplasms of the rectum have increased 10- to 30-fold in frequency over the past 45 years in Germany. Endoscopic ultrasonography is the method of choice for exact determination of the size of the tumor, depth of infiltration and detection of local lymph node metastases. Well-differentiated neuroendocrine tumors ≤ 10.0 mm in size that do not infiltrate the muscularis propria can be endoscopically resected. In the case of lymphatic or blood vessel invasion or spread to lymph nodes, surgical lymph node dissection is indicated. The management of well-differentiated, neuroendocrine rectal tumors 10.1-20 mm in size is still a matter of debate. Old age and multimorbidity favor a conservative endoscopic approach; however, in the case of fit young patients, surgical management has to be considered. For neuroendocrine rectal neoplasms ≥ 20 mm in size, the risk of metastatic spread increases to 60-80 % indicating that an endoscopic resection is not adequate. Due to the introduction of screening colonoscopy, neuroendocrine rectal tumors are nowadays diagnosed mostly at a prognostically favorable early stage.
Keywords: Endoscopy; Endosonography; Rectal neuroendocrine tumors; Resection; Therapy.