A large fraction of cases are diagnosed after routine surgery for bowel obstruction. Others may be diagnosed incidentally, or after investigation for carcinoid syndrome. The tumor typically produces serotonin, Tachykinin peptides and other substances, which cause flushing, tachycardia, diarrhea and in some cases fibrosis of the heart valves. There are often several<unk>  and highly fibrotic tumors present in the<unk> . The tumors often spread to the mesenteries and the liver.
Small intestine neuroendocrine tumor
Pancreatic neuroendocrine tumor
Goblet cell carcinoid
Neuroendocrine tumor
VIPoma
Hereditary diffuse gastric cancer
Acinar cell carcinoma of the pancreas
Metastatic insulinoma