Symptoms associated with neuroendocrine tumors that are not carcinoid

For neuroendocrine tumor patients that are not Carcinoid (which means, their tumors secrete serotonin), there are a variations of symptoms based on the types of hormones your tumor can overproduce. Generally speaking, these are tumors that are caused from Pancreatic Neuroendocrine Tumors, also called Islet Cell Tumors but also lung, pituitary and adrenal glands. These are a few of the hormones that they overproduce and the symptoms.


These can occur in any part of the pancreas. The pancreas produces insulin, which controls the level of sugar in the blood. In people with an insulinoma, the tumour produces an abnormally high level of insulin, which causes low blood-sugar levels (hypoglycaemia).

A low blood-sugar level may cause symptoms such as:

  • headaches
  • confusion
  • trembling and palpitations
  • anxiety
  • eyesight changes
  • seizures
  • feeling weak.

A low blood-sugar level is most likely to occur first thing in the morning, when exercising or after missing a meal. You can often raise your blood-sugar level again by eating or by having a sugary drink.


Gastrinomas usually start in the pancreas or the upper part of the small bowel (duodenum). They may produce too much gastrin. Gastrin is a hormone that causes gastric acid to be made. High levels of gastric acid can lead to ulcers in the stomach, the gullet (oesophagus) and the small bowel. There may be several ulcers, which often don’t respond well to the usual ulcer medicines. This is often called Zollinger-Ellison syndrome.

Common symptoms include:

  • bleeding into the stomach
  • a hole (perforation) in the wall of the stomach or small bowel
  • tummy cramps or feeling bloated (due to narrowing of part of the bowel)
  • diarrhea
  • pale, greasy and offensive-smelling stools (steatorrhoea)
  • soreness and tightness in the gullet (oesophagitis).


These tumours occur most often in the pancreas. They usually produce too much glucagon, which is a hormone that helps control blood-sugar levels.

Common symptoms of a glucagonoma include:

  • anemia (a low level of red blood cells)
  • weight loss
  • high blood-sugar (diabetes)
  • a skin rash
  • blood clots.


These usually occur in the pancreas. They may produce too much of a substance called vasoactive intestinal peptide.

Common symptoms include:

  • watery diarrhea
  • low levels of potassium as a result of the diarrhea
  • feeling weak and tired
  • feeling sick (nauseated) and being sick (vomiting).


Somatostatinomas are extremely rare tumours that usually occur in the pancreas or parts of the small bowel (the duodenum or jejunum). They produce extra somatostatin.

Common symptoms of a somatostatinoma include:

  • pale, greasy and offensive-smelling stools (steatorrhoea)
  • weight loss
  • anemia (a low level of red blood cells)
  • pain in the affected area
  • diarrhea
  • high blood-sugar (diabetes).


Can arise out of pituitary, lung or pancreatic NETs. These tumors produce excessive amounts of growth hormone release factor.

  • Elevated GF & IGF-1 levels
  • Rapid growth of hands and feet. (Acromegaly)


Arising from the pituitary gland, these tumors produce excessive amounts of the hormone ACTH. Too much ACTH increases the production of steroids, which can lead to weight gain, depression, easy bruising, increased risk of infection, and darkened skin.

NETs that don’t cause symptoms

Some tumors don’t overproduce hormones and may not cause symptoms. These are known as non-functioning NETs.  They may be discovered by chance during an operation or a test being carried out for other reasons. Some experts believe that even these types of tumors overproduce pancreatic polypeptide (PP), which can be a marker, but has no clinical syndrome.