Overview

Pancreatic neuroendocrine tumors are a rare type of cancer that starts as a growth of cells in the pancreas. The pancreas is a long, flat gland that sits behind the stomach. It makes enzymes and hormones that help digest food.

Pancreatic neuroendocrine tumors start from the hormone-producing cells in the pancreas. These cells are called islet cells. Another term for pancreatic neuroendocrine tumor is islet cell cancer.

Some pancreatic neuroendocrine tumor cells keep making hormones. These are known as functional tumors. Functional tumors create too much of the given hormone. Examples of functional tumors include insulinoma, gastrinoma and glucagonoma.

Most pancreatic neuroendocrine tumors do not produce an excess amount of hormones. Tumors that don't produce extra hormones are called nonfunctional tumors.

Symptoms

Pancreatic neuroendocrine tumors sometimes don't cause symptoms. When they do, symptoms can include:

  • Heartburn.
  • Weakness.
  • Fatigue.
  • Muscle cramps.
  • Indigestion.
  • Diarrhea.
  • Weight loss.
  • Skin rash.
  • Constipation.
  • Pain in the abdomen or back.
  • Yellowing of the skin and the whites of the eyes.
  • Dizziness.
  • Blurred vision.
  • Headaches.
  • Increased thirst and hunger.

When to see a doctor

Make an appointment with a health care professional if you have any symptoms that worry you.

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Causes

Pancreatic neuroendocrine tumors happen when cells in the pancreas develop changes in their DNA. A cell's DNA holds the instructions that tell the cell what to do. The changes, which doctors call mutations, tell the cells to multiply quickly. The changes let the cells continue living when healthy cells would die as part of their natural life cycle. This causes many extra cells. The cells might form a mass called a tumor. Sometimes the cells can break away and spread to other organs, such as the liver. When cancer spreads, it's called metastatic cancer.

In pancreatic neuroendocrine tumors, the DNA changes happen in hormone-producing cells called islet cells. It's not clear what causes the changes that lead to cancer.

Risk factors

Factors that are associated with an increased risk of pancreatic neuroendocrine tumors include:

  • A family history of pancreatic neuroendocrine tumors. If a family member was diagnosed with pancreatic neuroendocrine tumor, your risk is increased.
  • Syndromes present at birth that increase the risk of tumors. Some syndromes that are passed from parents to children can increase the risk of pancreatic neuroendocrine tumors. Examples of these include multiple endocrine neoplasia, type 1 (MEN 1), von Hippel-Lindau (VHL) disease, neurofibromatosis 1 (NF1) and tuberous sclerosis. These inherited syndromes are caused by changes in the DNA. These changes allow cells to grow and divide more than needed.

There's no way to prevent pancreatic neuroendocrine tumors. If you develop this type of cancer, you didn't do anything to cause it.

Pancreatic neuroendocrine tumors care at Mayo Clinic

Aug. 12, 2023

Living with pancreatic neuroendocrine tumors?

Connect with others like you for support and answers to your questions in the Neuroendocrine Tumors (NETs) support group on Mayo Clinic Connect, a patient community.

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