Pancreatic Neuroendocrine Tumours

Pancreatic Cancer Action
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This booklet for patients and carers describes pancreatic cancer, its causes and symptoms. It gives detailed information on the diagnostic tests used and the stages of pancreatic cancer. It includes a section on what to ask your doctor, where to go for further information and a glossary to explain many of the terms used.

Neuroendocrine tumours (NETs) can either be benign (non-cancerous) or malignant (cancerous) and start in the cells of the neuroendocrine system.

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The neuroendocrine system is a network of endocrine glands and cells throughout the body. Endocrine glands produce and release hormones (which regulate some chemicals in our bodies) which are circulated around the body. Neuroendocrine tumours can therefore appear in various parts of the body.

Pancreatic neuroendocrine tumours form in the endocrine cells of the pancreas where insulin and other hormones are produced. These tumours are called pancreatic neuroendocrine tumours (or pNETs) or islet cell tumours. They are much less common then exocrine tumours and divided into functional or non-functional tumours. Functioning tumours produce hormones and therefore are normally detected earlier, they make up around a third of the endocrine tumours diagnosed. Non-functional tumours do not produce hormones but are more likely to be cancerous.

Most neuroendocrine tumours occur sporadically or out of the blue. However, there are some genetic dispositions that make them more likely including a genetic condition called Multiple Endocrine Neoplasia Type 1.

Types of neuroendocrine tumour are detailed in the table below

Tumour Location Information
Insulinoma Pancreatic islet cells Tumours in insulin producing cells. This leads to over production of insulin and the symptoms of diabetes and low blood sugar such as headaches, frequency urinating, thirst, sweating, vision problems, confusion and fits.
Gastrinoma Pancreatic islet cells Tumours in the cells that produce the hormone gastrin, prompting the stomach to make acid, aiding in digestion. These tumours can therefore lead to severe stomach ulcers, stomach cramps, bloating, bleeding and pale greasy stools (steatorrhea).
Somatostainoma Pancreatic islet cells Tumours in the cells that produce the hormone, somatostatin. This is the hormone that usually controls the switch off of other hormones in the pancreas. Therefore, a tumour in these cells will affect digestion as well as blood sugar control. It can lead to diabetes symptoms, gallstones and blockages in the bowel. Other symptoms include diarrhoea, weight loss and anaemia.
VIPoma Pancreatic islet cells Tumours in the cells that produce the hormone vasoactive intestinal peptide. This hormone relaxes the muscles in the stomach and bowel. Therefore, patients experience loose and frequent stools, loss of electrolytes (salts, sugars and ions) and dehydration. Fatigue, nausea and vomiting are also common.
Glucagonoma Pancreatic islet cells Tumours in the cells that produce hormones to prompt the body to produce glucagon. This raises blood sugar levels in the body and therefore when produced to excess result in diabetes symptoms, damage to nerves, metabolic problems, mouth sores and anaemia. Patients often experience rashes, blisters and skin conditions.

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Information Product № PCA0011v1 Published 03/10/2019
Last Updated 21/04/2022 Next Review Due 03/10/2022