Incidental endoscopic findings of a rare gastric neuroendocrine carcinoma concurrent with an uncommon primary duodenal adenocarcinoma: A case report

Gastric neuroendocrine tumors (NETs) are rare gastric tumors. They are often found during esophagogastroduodenoscopy (EGD) as multiple small intramucosa polyps or as a single large polypoid lesion. Gastric NETs are difficult to distinguish from gastric adenocarcinoma or lymphoma. NETs are uncommon tumors, usually poorly differentiated and highly malignant. They are typically accompanied by vascular invasion and metastasis and have an extremely poor prognosis. Here, we reported an NET of the stomach concurrent with primary duodenal adenocarcinoma. A 56‐year‐old woman had underlying adenocarcinoma of the lung and received regular chemotherapy. Because of upper abdomen discomfort, EGD was performed, which showed diffuse multiple polypoid lesions over the stomach and another protruding mass over the posterior wall of the duodenal bulb. Abdomen computed tomography and the pathological report confirmed the above diagnosis.