Symptoms of somatostatinoma

Somatostatinoma is a type of neuroendocrine tumour (NET) that usually starts in the pancreas or small bowel. Its symptoms can be vague. See your GP if you are worried.

Somatostatinomas make large amounts of the hormone somatostatin. You usually have symptoms caused by the increase in the amount of somatostatin in your body. Symptoms include tummy (abdominal) pain, diabetes and diarrhoea. You may also have symptoms caused by the tumour itself. 

These symptoms could be due to somatostatinomas, but can also be caused by other more common medical conditions. It’s important to get them checked by a doctor.

Symptoms caused by somatostatin

Somatostatin is a hormone that controls the production of other hormones by the pancreas. It also controls how the gut works. An increase in the amount of somatostatin can cause:


Diabetes is a condition where the blood sugar levels become too high. Between 60 and 90 out of every 100 people with somatostatinomas (60 to 90%) have diabetes. This is usually mild.


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).

Between 30 and 90 out of every 100 people with somatostatinomas (30 to 90%) have diarrhoea.


Gallstones are small stones that form in the gallbladder. Between 60 and 90 out of every 100 people with somatostatinomas (60 to 90%) have gallstones. This is also called cholelithiasis. 

Weight loss

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

Fatty poo (stools)

You may pass frequent, large bowel motions that:

  • are pale coloured
  • are smelly
  • float and are difficult to flush away

This is called steatorrhea.

Somatostatinoma syndrome is the name given to the collection of symptoms caused by having too much somatostatin in your body.

Symptoms caused by the tumour itself

Symptoms might include:

Tummy (abdominal) pain

More than 40 out of every 100 people with somatostatinomas (more than 40%) have tummy pain.


Jaundice is yellowing of the skin and whites of the eyes. The urine can get darker than normal and bowel motions may be lighter in colour. This is more common in people with somatostatinomas that start in the small bowel.

This happens because the cancer blocks a tube called the bile duct. The bile duct carries bile into the small bowel.

Jaundice is a medical emergency. Speak to your doctor or go to your local A&E if you think you have jaundice. 

Blockage in the bowel

Sometimes the cancer can block the bowel (bowel obstruction). Symptoms of bowel obstruction include:

  • griping pain in the tummy
  • feeling bloated
  • constipation and being unable to pass wind
  • feeling sick

A bowel obstruction is an emergency. You should see your doctor or go to A&E if you think you have a bowel obstruction.


Somatostatinomas can cause bleeding from the bowel or stomach. You may not be able to see any blood if it is a small amount. Or you may see blood in the vomit or poo. Over time, bleeding reduces the number of red blood cells in your blood (anaemia).

Speak to your doctor if you see blood in your poo, or if your stools are black or sticky.

When to see your doctor

You should see your doctor if you have any symptoms that are unusual for you, won’t go away, or are getting worse. Although your symptoms are unlikely to be cancer, it is important to get them checked by a doctor.
Last reviewed: 
14 Jul 2021
Next review due: 
14 Jul 2024
  • ENETS consensus guidelines for the management of patients with digestive neuroendocrine neoplasms: functional pancreatic endocrine tumor syndromes
    R T Jensen and others
    Neuroendocrinology, 2012. Vol 95, Pages 98-119

  • Pancreatic neuroendocrine tumors: clinical features, diagnosis and medical treatment: advances
    T Ito, H Igarashi and R Jensen
    Best Practice and Research Clinical Gastroenterology, 2012. Vol 26, Issue 6, Pages 737-753

  • Somatostatinoma syndrome
    P Economopoulos and C Christopoulos
    Annals of Gastroenterology, 2001. Vol 14, Issue 4, Pages 252-260

  • Cancer: Principles and Practice of Oncology (11th edition)
    VT DeVita, TS Lawrence, SA Rosenberg
    Wolters Kluwer, 2019

  • Gastrointestinal neuroendocrine tumors: pancreatic endocrine tumors
    D Metz and R Jensen
    Gastroenterology, 2008. Vol 135, Issue 5, Pages 1469-1492

  • Diagnosing and treating NET-related diarrhea
    Lisa Astor
    2017 NANETS Symposium, 2017

Related links