Symptoms of stomach NETs

Many people with a stomach neuroendocrine tumour (NET) do not have any symptoms. Doctors often diagnose a stomach NET when looking for something else.

Stomach NETs might be found during an endoscopy test to investigate:

  • unexplained and unspecific abdominal (tummy) problems
  • having low amounts of red blood cells (anaemia)
  • indigestion

An endoscopy is a test that looks inside the body. The endoscope is a long flexible tube which has a tiny camera and light on the end of it.


If you do have symptoms, they might be non specific and be similar to other conditions that aren’t a neuroendocrine tumour. These symptoms might be caused by the tumour itself. Or they might be caused by a NET that has spread to a different part of the body.


You might have pain that comes and goes. Some people have pain for several years before a diagnosis of a neuroendocrine tumour.

Feeling or being sick

You might be feeling sick (nauseous) and be sick.

Breathlessness or looking pale

You might feel breathless or look pale. Rarely stomach NETs can cause bleeding in the digestive system. Over time this causes a drop in the number of red blood cells in your blood (anaemia). It is this that can make you feel breathless or look pale.

Dark poo (blood in your stool) or blood in vomit

Your poo may be darker, almost black, if your stomach is bleeding. Or if you’re sick you might see blood in your vomit. These are symptoms of bleeding in the digestive system.

Weight loss

You might lose weight even if you haven't changed your diet.


Diarrhoea means having more than 3 watery poos (stools) in a 24 hour period. You might also have diarrhoea at night and problems controlling your bowels (incontinence).

You might have ongoing diarrhoea, that can’t be explained.

Carcinoid syndrome

Some stomach NETs that have spread to the liver might cause a collection of symptoms called carcinoid syndrome. This is rare.

When to see your GP

You should see your doctor if you have any of these symptoms, or other changes that are unusual for you or that won't go away. Your symptoms are unlikely to be cancer but it is important to get them checked by a doctor.

Getting diagnosed

Find out more about seeing your GP, when you might be referred to a specialist and the tests used to diagnose stomach NETs.

  • Gastroenteropancreatic neuroendocrine neoplasms: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up
    M. Pavel and others
    Annals of Oncology 2020, Vol 31, Issue 5 

  • Gastrinomas: Medical or Surgical Treatment
    Jeffrey A. Norton and others
    Endocrinology and Metabolisms Clinic of North America. Sept 2018

  • Neuroendocrine of the stomach (gastric carcinoids) are on the rise: small tumours, small problems?
    H Scherubl and others
    Endoscopy, 2010. Issue 42 

Last reviewed: 
21 May 2021
Next review due: 
20 May 2024

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