A pancreatic islet cell tumor is a tumor that develops in the pancreas from a type of cell called an islet cell. These cells manufacture and release hormones, such as insulin and glucagon, into the bloodstream. An islet cell tumor can be benign (noncancerous) or malignant (cancerous). Depending on the type of islet cell tumor, an overproduction of certain hormones can result.

An islet cell tumor is rare, but it can cause a variety of symptoms depending on the type of hormone that it produces. If the tumor is malignant and spreads to other parts of the body, the cancer can become very serious.

Other names for a pancreatic islet cell tumor are:

  • islet of Langerhans tumor
  • pancreatic endocrine tumor
  • neuroendocrine tumor

Islet cell tumors can be either nonfunctional or functional.

Nonfunctional Islet Cell Tumors

Nonfunctional islet cell tumors produce substances that don’t cause symptoms. The only symptoms are those that result from the growth and spread of the tumor. These tumors are usually malignant.

Functional Islet Cell Tumors

Functional tumors are those that produce a hormone that results in symptoms. The three main types of functional tumors are gastrinomas, insulinomas, and glucagonomas. Other functional tumors exist that are extremely rare.


A gastrinoma occurs when the tumor grows from islet cells that make the hormone gastrin. Gastrin helps release acid in the stomach for food digestion.


An insulinoma is a tumor that produces the hormone insulin. Insulin is responsible for controlling sugar in the bloodstream.


A tumor that produces the hormone glucagon is known as a glucagonoma. This hormone causes the liver to release glucose, or sugar, into the bloodstream.

Rare Functional Tumors

A few types of functional islet cell tumors are extremely rare. These include tumors that produce vasoactive intestinal peptide (VIP), which are called VIPomas.

Somatostatinomas are another type of functional islet cell tumor that’s extremely rare. They make the hormone somatostatin. These hormones control sugar, water, and salt levels in the body.

The symptoms that result from having an islet cell tumor vary depending on the type of tumor. The symptoms of nonfunctional tumors arise from the growth and spread of the tumor. The symptoms of functional tumors depend on the hormone produced and released into the bloodstream.

Symptoms of a Nonfunctional Tumor

The symptoms of nonfunctional tumors include:

  • indigestion
  • increased gas
  • diarrhea
  • abdominal or back pain
  • abdominal mass
  • yellowing of the skin and the whites of the eyes, which is called “jaundice” or “icterus”

Symptoms of a Gastrinoma

The symptoms of a gastrinoma include:

  • recurring stomach ulcers
  • abdominal pain that responds to antacids
  • stomach contents flowing back up the esophagus
  • diarrhea

Symptoms of an Insulinoma

An insulinoma can cause an elevated heart rate and low blood sugar. The symptoms of low blood sugar are:

  • a headache
  • lightheadedness
  • blurred vision
  • weakness
  • shaking
  • irritability
  • hunger

Symptoms of a Glucagonoma

The symptoms of a glucagonoma include:

  • a rash on the stomach, legs, or face
  • diarrhea
  • unexplained weight loss
  • tongue and mouth sores

A glucagonoma can cause a blood clot, which can cause the following symptoms:

  • shortness of breath
  • chest pain
  • cough
  • pain in an arm or leg
  • swelling of an arm or leg
  • warmth of an arm or leg

A glucagonoma can also cause high blood sugar, which can cause the following symptoms:

  • headaches
  • dry skin
  • frequent urination
  • hunger
  • thirst

An Islet cell tumor is a very rare type of tumor. The only known risk factor for developing such a tumor is having a disease called multiple endocrine neoplasia type 1 syndrome (MEN1) or having a family history of the syndrome. MEN1 is an inheritable disease that causes one or more endocrine glands to be overactive or to grow a tumor. The endocrine glands affected by MEN1 include the pancreas, parathyroid, and pituitary gland.

There are several ways your doctor may diagnosis an islet cell tumor. The first step is to complete an overall physical exam and review of medical and family history. The next step is to either run a blood test or perform an imaging technique to look for a tumor.

Blood tests look for increased levels of hormones such as insulin, glucagon, and gastrin, as well as glucose levels in the bloodstream. These levels can indicate an islet cell tumor.

Imaging tests allow your doctor to visualize your pancreas and look for the presence of a tumor. These tests may include an ultrasound, magnetic resonance imaging, or a CT scan. Another way to get an image of the pancreas is to perform minor exploratory surgery. Your doctor may want to insert a small camera called an endoscope to view your pancreas or to take a small sample of the tissue for a biopsy.

Surgery is the most common treatment for cancerous tumors. The purpose of the surgery is to remove as much of the tumor as possible. If the tumor is present in other areas of your body, such as the liver, your surgeon may remove it from those locations as well.

If the cancer is widespread throughout your body, you may need chemotherapy to decrease the size of the tumors.

When an islet cell tumor is benign, the treatment may simply involve medications that treat the symptoms of the overproduced hormone. A functional tumor is typically benign. If the symptoms are severe, surgery to remove the tumor may be necessary.

If your doctor finds a cancerous tumor before it spreads beyond the pancreas, the outlook is good. Surgery to remove it usually cures the cancer. The more the cancer cells spread throughout the body, the lower the chances of recovery are.

If the tumor is benign, the outlook is also good. Doctors can usually remove the benign tumor and cure the disease through surgery. Medications can relieve symptoms brought about by excess hormones.