Login to Pancreatic Cancer UK

Pancreatic neuroendocrine tumours (PNETs)

Pancreatic neuroendocrine tumours (PNETs) start in the cells in the pancreas that produce hormones, called endocrine cells or Islet of Langerhans cells.

Neuroendocrine tumours (NETs) are tumours that start in the neuroendocrine system throughout the body. The neuroendocrine system produces hormones which help to control how our body works. Neuroendocrine tumours can be non-cancerous (benign), or cancerous (malignant).

The pancreatic endocrine cells produce hormones, including insulin and glucagon, which control the sugar levels in your blood. About one or two in a hundred pancreatic cancers (1-2%) are PNETs.

Some pancreatic neuroendocrine tumours produce specific hormones, which can cause specific symptoms.These are called functioning PNETs. About 10-30 in 100 (10-30%) pancreatic neuroendocrine tumours produce hormones.

However, most PNETs don’t produce hormones that cause specific symptoms. These are called non-functioning PNETs. Rarely, they can cause symptoms such as pain, weight loss, jaundice,or diarrhoea, which are similar to the symptoms of pancreatic ductal adenocarcinoma.

Non-functioning pancreatic neuroendocrine tumours can be harder to detect and diagnose than functioning neuroendocrine tumours. This is because they don’t cause specific symptoms. They are often diagnosed during tests for another problem.

Functioning neuroendocrine tumours

There are different types of functioning pancreatic neuroendocrine tumours.


Gastrinomas occur anywhere in the pancreas, and also the duodenum (first part of the small intestines). They produce too much of a hormone called gastrin, and can cause ulcers in the stomach or duodenum. Symptoms may include tummy (abdominal) pain, heartburn and diarrhoea (loose watery stools).

Gastrinomas are linked to a condition called Zollinger-Ellison Syndrome. People with a family cancer syndrome called Multiple endocrine neoplasia type 1 (MEN1) are more likely to get gastrinomas.


Insulinomas can occur anywhere in the pancreas. Most are not cancerous (benign). They produce too much of the hormone insulin, causing low blood sugar levels (hypoglycaemia). Symptoms of low blood sugar levels may include weakness, sweating, drowsiness, dizziness and lack of energy.


These tumours are mostly found in the body and tail of the pancreas. They produce too much of the hormone glucagon. Symptoms of glucagonomas include a distinct type of skin rash (redness, ulcers and scabbing), diabetes, anaemia (lack of red blood cells), weight loss and a sore mouth and tongue.


These tumours mostly occur in the head of the pancreas. They produce too much of a hormone called somatostatin. They can cause gallstones, diabetes, diarrhoea and steatorrhoea (large, pale, oily poo that smells horrible and is difficult to flush down the toilet), weight loss and blockage in the bowel.However, symptoms may be vague, and some people may not have any symptoms.


VIPomas are more common in the tail of the pancreas. They produce too much of a hormone called vasoactive intestinal peptide (VIP). Symptoms include lots of watery diarrhoea and abdominal pain.

Finding out more

Speak to your medical team with any questions about your PNET or treatment.

The NET Patient Foundation has more detailed information about diagnosing, treating and managing PNETs. It also provides support for people affected by all types of neuroendocrine tumours.

Questions to ask

  • What type of pancreatic neuroendocrine tumour do I have?
  • Is it functioning or non-functioning?
  • How is this type of cancer treated?

Information Standard

Published August 2016

Review date August 2018

Read about pancreatic exocrine cancer

Find out more about other cancers linked with the pancreas

Read about other conditions of the pancreas