Signs and Symptoms of Neuroendocrine Tumor
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Most of the signs and symptoms of pancreatic neuroendocrine tumors (NETs) are caused by the excess hormones that the tumors release into the bloodstream.


These tumors make gastrin, a hormone that tells the stomach to make more acid. Too much gastrin causes a condition known as Zollinger-Ellison syndrome. The excess gastrin leads to the stomach making too much acid. This leads to stomach ulcers, which can cause pain, nausea, and a decreased appetite. If the ulcer is severe, it may start bleeding. If the bleeding is mild, it may lead to anemia (low red blood cell counts). If the bleeding is severe, it can be life-threatening. The excess acid can also be released into the small intestine, where it can damage the intestinal lining cells and break down digestive enzymes before they have a chance to digest food. This can lead to diarrhea and weight loss. The ulcers in patients with gastrinomas can be hard to treat, requiring high doses of anti-ulcer medication to heal. Patients need to stay on these drugs for a long time, because the ulcers tend to come back again if treatment is stopped. Most gastrinomas are cancers.


These tumors make glucagon, a hormone that increases glucose levels in the blood. Excess glucagon can cause blood sugars to go up, sometimes leading to diabetes. Patients also experience problems with diarrhea, weight loss, and malnutrition. The nutrition problems can lead to symptoms like irritation of the tongue and the corners of the mouth (these are known as glossitis and angular cheilosis, respectively). Most of these symptoms are mild and more often caused by something else. The symptom that brings most people with glucagonomas to their doctor is a red rash that causes swelling and blisters. This rash may travel place to place on the skin. It is called necrolytic migratory erythema and it is the most distinctive feature of a glucagonoma. Most of these tumors are cancers.


These tumors make insulin, which lowers blood glucose levels. Too much insulin leads to low blood sugar (hypoglycemia), with symptoms like weakness, confusion, sweating, and rapid heart beat. When blood sugar gets very low, it can lead to the patient passing out or even going into a coma and having seizures. The symptoms of an insulinoma improve if the patient gets sugar -- either by mouth (as food) or as an injection into the vein (IV). Most insulinomas are benign (not cancers).


These tumors make somatostatin, which helps regulate other hormones. Symptoms of this type of tumor include diarrhea, diabetes, and gallbladder problems. The problems with the gallbladder can lead to abdominal pain, nausea, poor appetite, and jaundice (yellowing of the skin). Since symptoms of a somatostatinoma tend to be mild and are more often caused by other things, these tumors tend to be diagnosed at an advanced stage. Most somatastatinomas are cancers. Often, they are not found until they spread to the liver, when they cause problems like jaundice and pain.


These tumors make a substance called vasoactive intestinal peptide (VIP). Too much VIP can lead to problems with diarrhea and low blood levels of potassium. Patients also have low levels of acid in their stomachs, leading to problems digesting food. They may also have high blood glucose levels. The diarrhea may be mild at first, but gets worse over time. By the time they are diagnosed, most patients have severe, watery diarrhea, with as many as 20 bowel movements per day. Most VIPomas are cancers.


These tumors make pancreatic polypeptide, which helps regulate both the exocrine and endocrine pancreas. Most PPomas are cancers, and cause problems including abdominal pain and an enlarged liver. Some patients also get watery diarrhea.

Non-functioning tumors

These tumors do not make hormones, so they do not cause symptoms in early stages. Most of these are cancers and start to cause problems as they get larger or spread outside of the pancreas. When they spread, they most often spread to the liver. This can cause the liver to enlarge, which can cause pain and a poor appetite. It can also interfere with the liver function, sometimes leading to jaundice (yellowing of the skin) and abnormal lab tests.

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