Diagnosing somatostatinoma

You have some tests to diagnose a somatostatinoma. This might include blood tests and an endoscopy.

Somatostatinoma is a type of neuroendocrine tumour (NET). They usually start in the neuroendocrine cells of the pancreas or small bowel. Somatostatinomas make large amounts of the hormone somatostatin. So you might see your GP because of symptoms caused by having too much somatostatin in your body.

Somatostatinomas are rare cancers. So your doctor might ask you to have tests that check for other conditions first.

Seeing your GP

You usually start by seeing your GP. They will ask you about your general health, symptoms and may also examine you. 

Your GP might check your blood pressure, heart rate and temperature. They may arrange for you to have blood tests. Your doctor will then decide if you need to see a specialist.

Referral to a specialist

Your GP looks at your symptoms and decides what specialist to refer you to. For example, they might refer you to the gastrointestinal team (GI) if you have tummy pain or diarrhoea.

The specialist might ask you to have more tests. If tests show that you have a neuroendocrine tumour, your specialist will refer you to a team of doctors and specialist nurses who have expertise in treating NETs.


You have tests to check whether you have a NET, the type of NET you have, the size of the tumour and whether it has spread. This helps your doctor plan your treatment.

A blood test to check the amount of somatostatin

This test measures the amount of the hormone somatostatin in your body. You must not eat anything between 8 and 12 hours before having this test.

Blood tests

Blood tests can check your general health. They can also check the levels of certain substances in the blood which are sometimes raised with NETs. 

You may also have a blood test to check for a rare inherited condition called multiple endocrine neoplasia 1 (MEN1). This test is usually only requested by specialist doctors (genetic doctors). 

CT scan

This can show up a NET and see whether it has spread anywhere else in your body.

MRI scan

An MRI scan takes detailed pictures of your body. You might have an MRI scan to check if your NET has spread to other parts of the body such as the liver.


This test looks at the inside of your food pipe, stomach and bowel. Your doctor uses a long flexible tube which has a tiny camera and a light on the end of it. Doctors can take samples of any abnormal areas (biopsies).

Endoscopic ultrasound scan (EUS)

This test combines an ultrasound and endoscopy to look at the inside of your food pipe, stomach, pancreas and bile ducts. 

Your doctor uses a long flexible tube (endoscope) with a tiny camera and light on the end. It also has an ultrasound probe. The ultrasound helps the doctor find areas that might be cancer. They then can take samples (biopsies) of any abnormal areas.


ERCP stands for endoscopic retrograde cholangio pancreatography. It can help to look for abnormal areas in the liver, bile duct, pancreas or gallbladder.

You might have an ERCP if you have yellowing of the skin and whites of the eyes (jaundice). Your doctor might put a stent into the bile duct to help with the symptoms of jaundice at the same time. 

Radioactive scan

These are octreotide scans (or octreoscans) or gallium PET scans. You have an injection of a low dose radioactive substance, which is taken up by some NET cells. The cells then show up on the scan.

Surgical biopsy

Your surgeon takes samples of tissue during an operation called a laparotomy. You might have this if the tumour is hard to reach.

You may have other tests, depending on your symptoms. Your doctor can tell you which tests you need.
Last reviewed: 
14 Jul 2021
Next review due: 
14 Jul 2024
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    M. Pavel and others
    Annals of Oncology 2020, Vol 31, Issue 5 

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