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Pancreatic Neuroendocrine Tumors (NETs)

What Are Pancreatic Neuroendocrine Tumors (NETs)?

Pancreatic neuroendocrine tumors (NETs) grow in your pancreas. Your pancreas has two jobs: It makes juices to digest food, and it makes hormones to control body functions. NETs grow in the cells that make hormones.

These tumors can cause serious problems, but they usually don't grow as fast as the more common kind of pancreatic cancer. Treatments can remove them, slow their growth, and make your symptoms better. Every situation is different, and your treatment will depend on what kind of NET you have.

There are two kinds of NETs: functional and nonfunctional. Functional means the tumor makes hormones. Nonfunctional means it doesn't.

  • Functional. Most NETs are this type. They can be cancerous, meaning they can spread to other parts of your body, but they aren't always.
  • Nonfunctional. Most of these are cancerous. You may not have symptoms until your tumors get big or spread.

Functional NETs get their names from the type of hormone they make.

Insulinomas are the most common. They grow in the cells that make insulin. The extra insulin can lead to low blood sugar levels, which can make you feel "off" or pass out, or cause a seizure. These tumors are rarely cancerous.

Glucagonomas grow in the cells that make glucagon, a hormone that raises your blood sugar. They can cause high blood sugar levels, which can damage your nerves, eyes, heart, kidneys, and gums. Most of these tumors are cancerous.

VIPomas grow in the cells that make vasoactive intestinal peptide (VIP), which helps control muscles and nerves in the stomach and intestine. This type of NET is rare. About half of VIPomas are cancerous.

Gastrinomas happen in people with a rare disorder called Zollinger-Ellison syndrome. These tumors grow in the cells that make gastrin, which controls stomach acid. Most are cancerous.

Somatostatinomas grow in the cells that make somatostatin. This hormone helps control the production of other hormones, including insulin and gastrin. Most are cancerous.


No one knows what causes pancreatic NETs. People who have family members with a disorder called multiple endocrine neoplasia type 1 (MEN1), which can also affect the pancreas, are more likely to get it.

Other tumor-causing diseases that are passed down in families also raise your chances, including:

  • Von Hippel-Lindau syndrome
  • Neurofibromatosis type 1
  • Tuberous sclerosis


Because nonfunctional NETs often don't cause symptoms until they become large or spread, doctors usually find them at a later stage.

You may have:

  • Diarrhea
  • An uncomfortable feeling of fullness after eating
  • A lump in your belly
  • Pain in your belly or back
  • Yellowish skin or eyes

The symptoms of a functional NET depend on the kind of hormone it makes. You might feel:

  • Tired
  • Nervous or anxious
  • Confused
  • Shaky, dizzy, or lightheaded
  • Thirsty
  • More or less hungry than usual

You could have:

  • Weight loss or gain
  • Diarrhea
  • A need to go to the bathroom more or less
  • Pain in a specific place that won't go away
  • Reflux, a backup of stomach acid into your throat
  • A cough
  • A headache
  • Trouble seeing
  • A fast heartbeat
  • Sweating a lot
  • A raised, red rash on your lower leg, around your mouth, or anywhere your skin rubs together

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