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Patient Education - Endocrine Encyclopedia

Endocrine Surgery Encyclopedia

Pancreatic islet cell tumor

A pancreatic islet cell tumor is an uncommon tumor of the pancreas that arises from a distinct type of cell in the pancreas, the islet cell. Normally, islet cells produce insulin and other hormones, and islet cell tumors can also produce hormones.

Alternative Names: Islet cell tumors; Islet of Langerhans tumor; Neuroendocrine tumors

Causes, incidence, and risk factors:
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 secrete only one specific hormone that leads to specific symptoms. Pancreatic islet cell tumors can be benign or malignant (cancerous).

Islet cell tumors include insulinomas, glucagonomas, and gastrinomas (Zollinger-Ellison syndrome). A family history of multiple endocrine neoplasia, type I (MEN I) is a risk factor for the development of islet cell tumors.


  • Sweating
  • Tremor
  • Rapid heart rate
  • Anxiety
  • Hunger
  • Dizziness
  • Headache
  • Clouding of vision
  • Confusion
  • Behavioral changes
  • Convulsions
  • Loss of consciousness
  • Skin rash that migrates on the face, abdomen, perineum, buttocks, or lower extremities
  • May be crusty and scaly
  • May have raised lesions filled with clear fluid or pus
  • Inflamed mouth and tongue
  • Weight loss
  • Weight gain (unintentional)
  • Peptic ulcer pain
  • Vomiting blood
  • Diarrhea
  • Abdominal pain

Note: The symptoms depend upon the type of tumor and the hormone produced.

Signs and tests:

The type of tests performed may vary depending upon the symptoms associated with the condition. Some of the following abnormalities may be detected on testing:

  • an abdominal CT scan may reveal a pancreatic tumor (sometimes the tumor may be too small to see with a CT scan)
  • MRI of abdomen to show pancreatic tumor (MRI can sometimes see smaller tumors than those seen with a CT scan)
  • abnormal glucose tolerance test
  • low fasting glucose level
  • elevated serum insulin C-peptide
  • elevated serum insulin level
  • increased gastrin level
  • positive secretin stimulation test for pancreas
  • elevated fasting glucose level
  • elevated serum glucagon level
  • abdominal ultrasound
  • endoscopic ultrasound
  • intraductal endoscopic ultrasound
  • occasionally, the diagnosis and treatment (surgical removal) requires exploratory surgery, during which the surgeon feels the pancreas and may use ultrasound probes

Treatment will depend upon the type of tumor discovered and whether the tumor is benign or malignant. Malignant tumors spread to other organs, grow aggressively, and may not be treatable. In general, tumors are removed surgically, if possible.

If malignant cancerous cells spread (metastasize) to the liver, a portion of the liver may also be removed, if possible. If the cancer is widespread, various forms of chemotherapy may be used to shrink the tumors.

If the abnormal production of hormones is causing problems, medications may be given to counteract their effects. For example, the overproduction of gastrin in the case of gastrinomas results in oversecretion of acid in the stomach, and medications that block acid secretion can be taken to reduce symptoms.

Support Groups:

Expectations (prognosis):
Patients may be cured if tumors are surgically removed before they have spread to other organs. If tumors are malignant, chemotherapy may be used, but is usually unsuccessful at curing patients. Death may result from serious problems due to excess hormone production (hormone crises), such as very low blood sugar or from widespread metastasis.

Metastasis (spread) of the tumor to the liver can occur. Hormone crises can occur, depending on whether the cells that make up the tumor secrete hormones and what type of hormones are made. Gastrinomas can induce severe ulcers in the stomach and small intestine.

Calling your health care provider:
Call your health care provider if symptoms of this tumor develop, especially if you have a family history of MEN1.

There is no known prevention for these tumors.

Review Date: 5/4/2004
Reviewed By: Stephen Grund, M.D., Ph.D., Chief of Hematology/Oncology and Director of the George Bray Cancer Center at New Britain General Hospital, New Britain, CT. Review provided by VeriMed Healthcare Network.

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Diseases of the Endocrine System

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