What are insulinomas?

Insulinomas are rare neuroendocrine tumours (NETs) that start in the insulin making cells of the pancreas. These cells are called islet cells. So insulinomas are also called islet cell tumours. 

Neuroendocrine cells of the pancreas make different types of hormones which help the body to break down food.

Insulinomas make the hormone insulin. Insulin controls the amount of sugar (glucose) in the blood.

The pancreas

The pancreas is part of our digestive system.

Diagram showing where the pancreas is in the body in relation to the other organs. This includes the stomach, liver, bowel and gallbladder.

The pancreas is quite high up in the tummy (abdomen). It lies across your body where the ribs meet at the bottom of the breastbone, just behind your stomach. It is about 6 inches (15 centimeters) and shaped like a leaf. 

The pancreas has 3 parts:

  • the wide part is the head
  • the thin end is the tail
  • the part in the middle is the body
Diagram showing 3 parts of the pancreas

The pancreatic duct is a tube that collects the digestive juices made by the pancreas and carries them into the first part of the bowel (duodenum).

What the pancreas does

The pancreas makes digestive juices, as well as different types of hormones such as insulin. The part of the pancreas that makes digestive juices is the exocrine pancreas. The part which produces hormones, including insulin, is called endocrine pancreas.

Insulin is a hormone that controls the amount of sugar (glucose) in the blood. It helps glucose to move from the blood into body cells. This reduces the amount of glucose in the blood and lowers the blood sugar level.

How common is an insulinoma?

Insulinomas are very rare. Only between 1 and 32 people in every million develop an insulinoma every year. 

Between 1 and 2 out of every 100 pancreatic cancers (1% to 2%) diagnosed every year are insulinomas. Around 10,300 people are diagnosed with pancreatic cancer in the UK each year.

Cancer or non cancer?

All insulinomas are cancer. Most are diagnosed early and you might be able to have surgery to cure it. Other insulinomas spread to other parts of the body (metastases). 

Less than 10 in every 100 insulinomas (less than 10%) spread to other parts of the body. The most common places where insulinomas spread to are the lymph nodes and liver.

Last reviewed: 
01 Jul 2021
Next review due: 
01 Jul 2024
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