Cryo-EM structures of a pentameric ligand-gated ion channel in liposomes.

Primary malignant tumors of small bowel constitute only about 1-2% of all gastrointestinal neoplasms. Although neuroendocrine tumors (NETs) are relatively rare, they still represent the second most common malignancy of the small bowel (after adenocarcinoma). Clinical manifestations include abdominal pain, bowel obstruction, diarrhea, weight loss and bleeding. The differential diagnosis of obscure gastrointestinal bleeding can sometimes be challenging for endoscopy as well as for radiology methods. We present the case of an 80-year-old man suffering from severe hypochromic anemia. Routine endoscopic methods did not show any appropriate pathology. Finally, a single ulcerative infiltration of the ileum was diagnosed by capsule endoscopy (CE). CT enterography did not reveal any other lesions. In accordance with a positive chromogranin A, endoscopic and radiologic methods, a suspicion of NET was expressed. During the surgery, 7 lesions were found and a resection of 120 cm of ileum was performed. The histology confirmed a diagnosis of NET grade 1, with a total number of 15 NET lesions in the specimen. The following octreotide scan did not show any residual infiltration. We present a patient with 15 NET lesions in the ileum diagnosed by CE and successfully cured by surgical resection of the ileum. Key words: capsule endoscopy - carcinoid syndrome - gastrointestinal carcinoids - neuroendocrine tumor - obscure gastrointestinal bleeding - small bowel - surgery.