Pancreatic neuroendocrine tumors (pNET) are a group of cancers that can occur in the hormone-producing cells of the pancreas. Pancreatic neuroendocrine tumors, also known as islet cell cancers, are very rare.

Pancreatic neuroendocrine tumors begin in small hormone-producing cells (islet cells) normally found in your pancreas.

Some pancreatic neuroendocrine tumor cells continue to secrete hormones (known as functional tumors), creating too much of the given hormone in your body. Examples of these types include gastrinoma and glucagonoma.

Many times these tumors do not secrete an excess amount of these hormones (known as nonfunctional tumors).

Pancreatic neuroendocrine tumors at Mayo Clinic


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

  • Stomach ulcers
  • Heartburn
  • Diabetes
  • Weakness
  • Fatigue
  • Muscle cramps
  • Indigestion
  • Diarrhea
  • Weight loss
  • Skin rash
  • Constipation
  • Pain in your abdomen or back
  • Yellowing of your skin or eyes
  • Low blood sugar


It's not clear what causes most pancreatic neuroendocrine tumors.

Pancreatic neuroendocrine tumors occur when hormone-producing cells in the pancreas (islet cells) develop changes (mutations) in their DNA — the material that provides instructions for every chemical process in your body. DNA mutations cause changes in these instructions. One result is that cells may begin to grow out of control and eventually form a tumor — a mass of cancerous cells. Sometimes the cancer cells break away and spread to other organs, such as the liver.

Some inherited syndromes increase the risk of this type of cancer, including:

  • Multiple endocrine neoplasia, type 1 (MEN 1) syndrome
  • Von Hippel-Lindau disease
  • Von Recklinghausen's disease (neurofibromatosis 1)
  • Tuberous sclerosis

Risk factors

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

  • Being male. Men are much more likely than women to develop these tumors.
  • A family history of pancreatic neuroendocrine tumors. If a family member was diagnosed with pancreatic neuroendocrine tumor, your risk is increased. You may have multiple endocrine neoplasia, type 1 (MEN 1) syndrome, which increases the risk of this type of tumor.

Pancreatic neuroendocrine tumors care at Mayo Clinic

June 05, 2021

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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