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HomeHealth articlespancreatic islet cell tumorPancreatic Islet Cell Tumor - Causes | Symptoms | Diagnosis | Treatment | Complications | Prevention

Pancreatic Islet Cell Tumor - Causes, Symptoms, Diagnosis, Treatment, Complications and Prevention

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A pancreatic islet cell tumor is a rare tumor involving islet cells of the pancreas. This article explains in detail about this condition.

Medically reviewed by

Dr. C. Elanchezhian

Published At April 26, 2022
Reviewed AtOctober 6, 2022

What Is Pancreatic Islet Cell Tumor?

A tumor or cancer is a mass formed by abnormal or uncontrolled growth of cells in our body. The pancreas is a deep-seated organ that sits behind and a bit below our stomach. The pancreas lets out juices into the intestine for digestion of food as well as releases some hormones as insulin into the bloodstream. These hormones are secreted from tiny islands of cells distributed widely in the pancreas. Pancreatic islet cell tumors arise when abnormal or uncontrolled growth happens in islet cells of the pancreas. It is a rare type of cancer. It is also called a pancreatic neuroendocrine tumor, pancreatic endocrine tumor, and pancreatic carcinoid.

How Is It Caused?

Hormones produced by the islet cells of the pancreas assist in the performance and maintenance of many functions in a healthy person. Some of the functions are maintenance of blood sugar level, production of acid in the stomach, regulation of intestinal secretions, and movement. When a tumor arises in islet cells of the pancreas, it may produce hormones in excess, leading to metabolic disturbances and some specific symptoms. However, a considerable proportion of these tumors actually do not secrete anything but rather grow out as a mass in the pancreas. Many of these tumors can also spread to other parts of the body, especially the liver. Fortunately, many of these tumors are slow-growing and do not spread early in the course of the disease.

Following are the common types of islet cell tumors:

The most commonly recognizable risk factor for contracting an islet cell tumor is a family history of multiple endocrine neoplasia type I (MEN I), a genetic syndrome with multiple tumors in the body. However, in most of the patients, there are no identified risk factors.

What Are the Symptoms?

There can be different types of symptoms produced by the tumors. It usually depends on the specific hormone type which is being secreted in excess by the tumor cells.

1. Insulinoma is the tumor type in which insulin is produced in an uncontrolled manner, leading to less than normally required blood sugar levels.

It may show the following symptoms:

  1. Nervousness, anxiety, irritation and unclear thinking.

  2. Headache, sweating, shivering, or shakiness.

  3. Tiredness, weakness, hunger.

  4. Double or blurred vision.

Extremely lowered blood sugar levels may lead to fainting, seizure, and in severe cases, may cause brain damage.

2. Gastrinomas lead to the over-production of the hormone gastrin. Its normal function in our body is to secrete stomach acid. In turn, gastrinoma leads to the excessive production of stomach acid, and the following symptoms may be seen:

  • Pain in the abdomen due to ulcerations in the stomach and small bowel.

  • Diarrhea or loose motions.

  • Occasional blood in stools or vomit.

3. Glucagonomas lead to the over-production of the hormone glucagon. Glucagon normally increases the blood sugar level during periods of fasting. So, overproduction leads to a persistent and uncontrolled increase in sugar levels in the blood.

The following symptoms can be seen:

  • Diabetes.

  • Frequent thirst.

  • Frequent urination.

  • Loss of weight.

  • Rashes in the groin or buttocks which are red and blistery.

4. Somatostatinomas lead to the excessive production of the hormone somatostatin, which normally suppresses or terminates the intestinal processes and food digestion.

It may show the following symptoms:

  • Loose motions with foul-smelling stools.

  • Gallstones.

  • Jaundice - yellowish discoloration of skin and eyes.

  • Increased blood sugar levels.

  • Loss of weight.

5. VIPomas over-produce the hormone vasoactive intestinal peptide (VIP). This hormone is concerned with the maintenance of the balance of water secretion and mineral salt absorption in the gastrointestinal tract. VIPomas may lead to the following symptoms:

  • Severe diarrhea can cause dehydration.

  • Cramps in the abdomen.

  • Decreased levels of blood potassium levels.

  • Increased calcium levels.

6. Non-functioning tumors are one of the most common types of islet cell tumors that form a mass and compress on the nearby other organs or, at times, spread to body organs.

How Is Pancreatic Islet Cell Tumor Diagnosed?

Patients generally present with symptoms of some excess hormone or symptoms caused by advanced tumors that have spread to the liver or lung.When you visit your physician, you will be asked about the signs and symptoms you are facing, your medical and personal history, and also your family history. Following this, you will be physically examined for any abnormality in the body.

Your physician may ask you to undergo various tests like:

1. Blood tests - They vary depending on symptoms but may include as follows:

  • Routine blood investigations like blood counts and biochemistry.

  • Fasting blood glucose level and glucose tolerance test.

  • Blood insulin level, insulin C-peptide level.

  • Gastrin level, glucagon levels, vasoactive intestinal peptide (VIP) level.

  • Fasting somatostatin level.

2. Following imaging tests may be required to locate and assess spread in the body:

  • Ultrasound of the neck and abdomen.

  • CT (computed tomography) scan of the chest, abdomen, and pelvis.

  • Endoscopic examination sometimes including endoscopic ultrasound.

  • PET (positron emission tomography) scan of the whole body.

Sometimes, if these tests fail to identify the exact part of the pancreas that has the tumor, then surgery can be performed to confirm the diagnosis and treat it in the same setting. In this case, the pancreas is examined for the location of the tumor using ultrasound inside the operation theatre.

How Can It Be Treated?

The treatment of these tumors depends on the exact specific type of tumor and stage of the disease. The best treatment for a tumor localized to the pancreas is surgery whenever possible. Some tumors that invade the liver can also be treated with surgery. For symptoms of hormone excess, suppressive medication can be prescribed.Treatment with chemotherapy is also a modality used in advanced cancer.

What Is the Prognosis?

The prognosis depends on a number of factors, the most important of which is the stage of the disease. If the treatment is done in the early stage, the prognosis is better than the more common pancreatic ductal carcinoma, which is the most common cancer of the pancreas.

Are There Any Possible Complications?

If pancreatic islet tumors are not managed in the early stages, there could be possible complications related to extreme abnormalities of blood sugar levels and hormone crisis, along with the possible spread of cancer to other body organs.

How Can It Be Prevented?

There are no known ways of preventing these tumors. Genetic counseling and work-up in people with known family history can help with early detection and treatment. For people without any hereditary risk factors, same as for all health-related symptoms, early reporting to the physician can help in early detection and treatment.


Pancreatic islet cell tumors are rare but may lead to severe complications if not managed early. Hence, early diagnosis and treatment are necessary. You can consult a specialist online regarding the signs and symptoms, diagnosis, and treatment of this condition via online medical platforms at the ease of your home.

Frequently Asked Questions


Which Type of Islet Cell Tumor Is the Most Common?

The islet cells in the pancreas produce hormones like insulin, somatostatin, glucagon, and pancreatic polypeptide. These hormones are responsible for regulating body sugar levels and the production of stomach acid. The abnormal growth of islet cells happens in islet cell tumors. There are various types, and the most common are insulinomas. It accounts for 60 % of all islet cell tumors. They can be non-cancerous (benign) or cancerous (malignant). The insulinomas decrease the blood sugar levels leading to headaches, tiredness, nervousness, hunger, etc.


How Are Pancreatic Islet Cell Tumors Classified?

The pancreatic cell tumors occur rarely and are classified depending on the excessive production of hormones secreted by the abnormal islet cell growth. It includes:
Insulinomas - The standard type that leads to excess insulin production.
Gastrinomas - The stomach acid levels increases due to excess gastrin hormone production.
Glucagonomas - The glucagon hormone is produced more, leading to increased blood sugar levels.
VIPomas - This tumor causes an imbalance in salt absorption and water secretion.
Stomatostatinomas - The digestion and absorption of food are greatly affected due to excess production of somatostatin.
Non-functioning tumors - The symptoms occur when cancer grows large.


How to Treat Pancreatic Neuroendocrine Tumors?

The pancreatic neuroendocrine tumors are treated as follows:
Surgery - The tumors present within the pancreas that has spread to the liver are treated by surgical removal.
Chemotherapy - Several drugs reduce the tumor size by killing the cancer cells.
Hormone therapy - Certain drugs suppress hormone production by various islet cell tumors.
Peptide receptor radionuclide therapy (PRRT) - The healthcare specialist administers a radioactive substance in the vein that targets the cancer cells and kills them.


Is Pancreatic Neuroendocrine Tumor Serious?

The pancreatic neuroendocrine tumor occurs rarely, and it can be benign or turn cancerous (malignant). Mostly, they do not show symptoms in the early stage. However, if they are diagnosed during the initial stages, the prognosis of treatment is significantly good. If the tumor turns malignant and spreads to other organs, the prognosis is low, and the following complications may occur.
Hormone crisis.
Abnormal blood sugar levels.


What Are the Symptoms of a Benign Pancreatic Tumor?

The several symptoms of benign (non-cancerous) pancreatic tumor are listed down:
Low blood glucose level.
Weight loss.
Muscle cramps.


What Are the Diagnostic Methods for Pancreatic Neuroendocrine Tumors?

The diagnosis of pancreatic neuroendocrine tumors are listed down:
Blood Investigations - The glucose, insulin, glucagon, and other cell counts are determined using blood examination.
Imaging Investigations - Various imaging modalities like computed tomography (CT) and magnetic resonance imaging (MRI) aid in determining the size and extent of the tumor.
Biopsy - The surgeon may surgically remove a tissue sample from the pancreas to confirm malignancy.


Does Islet Cell Tumor Turn Malignant?

The islet cell tumor develops from the islet cells of the pancreas. These cells are essential in regulating blood sugar levels, stomach acid production, and digestion. The abnormal growth of islet cells is termed an islet cell tumor; they mostly grow slowly and, in rare cases, turn cancerous and spread to other organs (mainly the liver). In such cases, the doctor may suggest surgery, chemotherapy, and other hormonal therapies to improve the prognosis.


How Do the Pancreatic Islet Cells Function?

The pancreas contains 3.2 to 14.8 million islet cells. The types and functions of pancreatic islet cells are as follows:
Alpha cells - It secretes glucagon hormone and releases glucose if your blood glucose level is low.
Beta cells - It produces insulin hormone that regulates the blood glucose level.
Delta cells secrete somatostatin hormone hinders the release of other pancreatic hormones (insulin, glucagon, etc.).
PP cells (pancreatic polypeptide) maintain the release of glucagon hormone.
Ghrelin-producing cells - The pancreas produces smaller amounts of Ghrelin hormone that stimulates hunger.


What Are the Antibodies Against the Pancreas?

The pancreas requires glutamic acid decarboxylase (GAD) to function well. In some instances, our immune system produces autoantibodies that attack normal cells in the body. When GAD autoantibodies are created, it attacks the beta cells of the pancreas. Thus, the insulin hormone levels that regulate our blood glucose levels are lowered. The doctor may test the presence of GAD autoantibodies to detect the type of diabetes as they are increased in individuals with type 1 diabetes.
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Dr. C. Elanchezhian
Dr. C. Elanchezhian

General Medicine


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