Pancreatic islet cell tumor

Causes

In the normal pancreas, cells called islet cells produce hormones that regulate a variety of bodily functions, such as blood sugar level and the production of stomach acid.

Tumors that arise from islet cells of the pancreas can also produce a variety of hormones, though some do not.

Although islet cells produce many different hormones, most tumors release only one hormone that leads to specific symptoms. Pancreatic islet cell tumors can be noncancerous (benign) or cancerous (malignant).

Islet cell tumors include:

• Gastrinomas (Zollinger-Ellison syndrome)
• Glucagonomas
• Insulinomas

A family history of multiple endocrine neoplasia, type I (MEN I) is a risk factor for islet cell tumors.

Symptoms

Symptoms depend on which hormone is made by the tumor.

For example, insulinomas produce insulin, which helps the body lower blood sugar levels. Symptoms may include:

• Feeling tired or weak
• Shaking or sweating
• Headache
• Hunger
• Nervousness, anxiety, or feeling irritable
• Unclear thinking or feeling uneasy
• Double or blurry vision
• Fast or pounding heartbeat

If your blood sugar gets too low, you may faint, have a seizure, or even go into a coma.

Gastrinomas make the hormone gastrin, which tells the body to make stomach acid. Symptoms may include:

• Abdominal pain
• Diarrhea
• Ulcers in the stomach and small bowel
• Vomiting blood (occasionally)

Glucagonomas make the hormone glucagon, which helps the body raise blood sugar levels. Symptoms can include:

• Diabetes
• Red, blistery rash in the groin or buttocks
• Weight loss

Exams and Tests

Blood tests may vary depending upon the symptoms, but may include:

• Fasting glucose level
• Gastrin level
• Glucose tolerance test
• Secretin stimulation test for pancreas
• Blood glucagon level
• Blood insulin C-peptide
• Blood insulin level

The following imaging tests may be performed:

• Abdominal CT scan
• Abdominal ultrasound
• Endoscopic ultrasound
• MRI of abdomen

A blood sample may also be taken from a vein in the pancreas for testing. 

Sometimes, surgery is needed to diagnose and treat this condition. During this procedure, the surgeon examines the pancreas by hand and with ultrasound.

Treatment

Treatment depends on the type of tumor and if it is cancerous.

Cancerous tumors can grow quickly, and spread to other organs. They may not be treatable. Tumors are usually removed with surgery, if possible.

If cancer cells spread to the liver, a part of the liver may also be removed, if possible. If the cancer is widespread, chemotherapy may be used to try and shrink the tumors.

If the abnormal production of hormones is causing symptoms, you may receive medications to counteract their effects. For example, with gastrinomas, the overproduction of gastrin leads to too much acid in the stomach. Medications that block acid release can reduce symptoms.

Outlook (Prognosis)

You may be cured if the tumors are surgically removed before they have spread to other organs. If tumors are cancerous, chemotherapy may be used, but it usually cannot cure patients.

Life-threatening problems (such as very low blood sugar) can occur due to excess hormone production, or if the cancer spreads throughout the body.

Possible Complications

• Diabetes
• Hormone crises (if the tumor releases certain types of hormones)
• Severe low blood sugar (from insulinomas)
• Severe ulcers in the stomach and small intestine (from gastrinomas)
• Spread of the tumor to the liver

When to Contact a Medical Professional

Call your health care provider if you develop symptoms of these tumors, especially if you have a family history of MEN I.

Prevention

There is no known prevention for these tumors.

Alternative Names

Islet cell tumors; Islet of Langerhans tumor; Neuroendocrine tumors

References

National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology: Neuroendocrine Tumors. National Comprehensive Cancer Network; 2011. Version 1.2011.

Jensen RT. Pancreatic endocrine tumors. In: Goldman L, Ausiello D, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011; chap 201.

Update Date: 3/14/2012

Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.