Pancreatic neuroendocrine tumours (PancNETs)

Pancreatic neuroendocrine tumours are often known as pancreatic NETs, PNETs or pancNETs.

Neuroendocrine tumours (NETs) grow in neuroendocrine cells found throughout the body. They start in the neuroendocrine cells in the pancreas called Islet of Langerhans cells (see diagram). Neuroendocrine cells produce hormones that help to control how our body works. Neuroendocrine tumours can be cancerous (malignant) or non-cancerous (benign), although they can all become cancerous.

Neuroendocrine Cancer UK has more detailed information about the different neuroendocrine tumours, including pancreatic neuroendocrine tumours.

The neuroendocrine cells in the pancreas produce hormones, including insulin and glucagon, which control the sugar levels in the blood. Four in a hundred pancreatic cancers (4%) are pancreatic NETs.

Pancreatic NETs are described as functioning or non-functioning tumours. This depends on whether they produce hormones and cause symptoms.

Functioning pancreatic neuroendocrine tumours

Some pancreatic NETs produce too much of certain hormones when the cells become cancerous. This can cause specific symptoms. These are called functioning pancreatic NETs. About 10-30 in 100 pancreatic neuroendocrine tumours (10-30%) are functioning.


Gastrinomas are found in the pancreas and the duodenum (first part of the small intestine). They produce too much of a gut hormone called gastrin, causing the production of too much stomach acid. Symptoms may include tummy (abdominal) pain, heartburn, diarrhoea and weight loss. Gastrinomas can cause ulcers in the stomach or duodenum, which can be life-threatening if they bleed severely.

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 They produce too much of the hormone insulin, causing the symptoms of low blood sugar levels (hypoglycaemia). These may include dizziness, sweating, palpitations (your heart feels like it is pounding, fluttering, or beating irregularly), drowsiness and confusion.


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


These tumours are mostly found in the head and tail of the pancreas. They produce too much somatostatin, a substance that affects the production and release of other gut hormones.

Somatostatinomas can cause tummy pain, gallstones, diabetes, diarrhoea, steatorrhoea (large, pale, oily poo that smells horrible and is difficult to flush down the toilet), low levels of stomach acid and weight loss. But 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, dehydration, high calcium levels in the blood and a flushed face.

Non-functioning pancreatic neuroendocrine tumours

Most pancreatic NETs don’t produce hormones that cause specific symptoms. These are called non-functioning pancreatic NETs. Rarely, they can cause symptoms that are similar to the symptoms of pancreatic ductal adenocarcinoma (the most common type of exocrine pancreatic cancer). These include pain, weight loss, jaundice,or diarrhoea.

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

Finding out more

Speak to your medical team with any questions about pancreatic neuroendocrine tumours and how they are treated.

Contact Neuroendocrine Cancer UK for more detailed information and support around diagnosing, treating, managing and living with a pancreatic NET. The support they offer includes a helpline, support groups, an online community and counselling.

Questions to ask your doctor or nurse

  • What type of pancreatic neuroendocrine tumour (pancNET or PNET) do I have?
  • Is it functioning or non-functioning?
  • Is the tumour cancerous?
  • How is this type of tumour treated?

Updated: November 2018

Review date: November 2021