AbstractNeuroendocrine neoplasms of the gastric tube are less common than adenocarcinomas. Topography includes stomach, small intestine, Vater ampulla, and gross intestine. They are graded as neuroendocrine tumors grade I and II (NETs GI and GII) and neuroendocrine carcinomas GIII based on Ki-67 index and mitotic count.[1] Endoscopic treatment for GI NETs ≤1 cm that does not extend beyond the submucosal layer and does not demonstrate lymph node metastasis is recommended. Tumors ≥2 cm, with lymph node metastasis, are indicated for surgical treatment. The treatment strategy for tumors between 10 and 20 mm in size remains controversial.[2] We present a rare case of a 60-year-old male patient with end-stage renal failure who underwent a screening pretransplantation endoscopic control. Colonoscopy had no pathological findings. Gastroscopy reveals an abnormal mucosa in the anterior upper part of the duodenal bulb that was described as a micronodular mucosa and a central nodule of 6 mm with erythematous mucosa. Histology of the micronodular mucosa reveals a heterotopic gastric mucosa and a small hyperplastic polyp. Biopsies from the nodule reveal a carcinoid tumor (NET GI). Immunohistochemistry: Positive chromogranin levels, low mitotic index (1/10 HPF), and Ki-67 index <1% [Figure 2]. Gastrin levels were normal and chromogranin levels were abnormal (314 ng/ml, ULN <120 ng/ml). Spiral tomography of the thorax and the abdomen were normal. Endoscopic submucosal dissection is indicated for small NETs (≤1 cm). Laparoscopic and endoscopic cooperative surgery is a novel method, but the experience is limited. Surgery is the best choice for large NETs (>2 cm) and those of the duodenal bulb with histological extensions and the lack of assessing depth invasion.