Pancreatic-islet cell tumors appear in one of two forms. They may be nonfunctioning or functioning tumors. Nonfunctioning tumors may cause obstruction in the shortest part of the small intestine (duodenum) or in the biliary tract, which connects the liver to the duodenum and includes the gall bladder. These nonfunctioning tumors may erode and bleed into the stomach and/or the intestines, or they may cause an abdominal mass.
Functioning tumors secrete excessive amounts of hormones, which may lead to various syndromes including low blood sugar (hypoglycemia), multiple bleeding ulcers (Zollinger-Ellison Syndrome), pancreatic cholera (Verner-Morrison Syndrome), carcinoid syndrome or diabetes.
Islet cells are small, isolated masses of cells that make up the Islet of Langerhans in the pancreas. When functioning normally, they secrete the protein hormones insulin and glucagon. Tumors composed of irregular islet cells may occur alone or in a group of many tumors. Approximately 90% of islet-cell tumors are noncancerous (benign). They usually range in size from 0.5 to 2 cm in diameter. .
Symptoms of pancreatic islet-cell tumor vary with the type of hormone- producing tumor that occurs. Generally, symptoms include periodic attacks of pain in the abdomen which increase in severity and frequency. Insulin- secreting tumors may result in abnormally low blood sugar (hypoglycemia), and may produce such symptoms as headache, visual disturbances, confusion, weakness, sweating, uncontrollable tremors or quivering, loss of muscular coordination (ataxia), personality changes, palpitations, convulsions or coma. Symptoms of severe hypoglycemia may be confused with those of many neurologic or psychiatric disorders.
Pancreatic islet-cell tumors which produce the hormone gastrin commonly result in multiple ulcers. Approximately 50% of these tumors are benign and their growth and spread are slow. Symptoms of ulcers may include gastrointestinal bleeding, stomach pain and diarrhea.
Zollinger-Ellison Syndrome is characterized by multiple ulcers which may be caused by gastrin secreting islet-cell tumors of the pancreas. These ulcers commonly bleed, cause stomach pain and diarrhea. (For more information on this disorder, choose "Zollinger-Ellison" as your search term in the Rare Disease Database).
Certain pancreatic islet-cell tumors which secret the hormone vasoactive intestinal polypeptide (VIP) are responsible for such symptoms as severe watery diarrhea, dehydration, intermittent vomiting, weight loss, weakness, decreased potassium in the blood (hypokalemia), excess calcium in the blood (hypercalcemia), reduced or absent gastric secretion and degenerative changes in the spine. This disorder is called Verner-Morrison Syndrome or Pancreatic Cholera.
The exact cause of pancreatic islet-cell tumors is not known. However scientists believe certain forms of this disorder may be inherited.
Human traits, including the classic genetic diseases, are the product of the interaction of two genes, one received from the father and one from the mother. Verner-Morrison syndrome and a particular form of Zollinger-Ellison syndrome are inherited as autosomal dominant traits.
In dominant disorders, a single copy of the disease gene (received from either the mother or father) will be expressed "dominating" the other normal gene and resulting in the appearance of the disease. The risk of transmitting the disorder from affected parent to offspring is 50 percent for each pregnancy regardless of the sex of the resulting child.
Symptoms of the following disorder can be similar to those of Pancreatic Islet-Cell Tumors. Comparisons may be useful for a differential diagnosis:
Hypoglycemia is characterized by abnormally low blood sugar, and may be caused by excess insulin in the body. Symptoms of hypoglycemia may include faintness, weakness, jitteriness, profuse perspiration, excessive hunger and nervousness. Islet-cell tumors of the pancreas may be one source of the excess insulin, although hypoglycemia often occurs for unknown reasons. (For more information on this disorder, choose "Hypoglycemia" as your search term in the Rare Disease Database.)
Small benign tumors at or near the surface of the pancreas can usually be surgically removed. If the tumor is large or deep into the body or tail of the pancreas, a portion of the pancreas may be removed. Total removal of the pancreas (pancreatectomy) is reserved only for large malignant tumors of the pancreas. Surgical cure rates are very high for small benign tumors. The drugs Diazoxide and Streptozocin (for insulinoma) are frequently administered to control symptoms or reduce the size of the tumor.
Gastrin secreting pancreatic islet-cell tumors (Zollinger-Ellison Syndrome) may be treated with the drug Cimetidine which greatly reduces gastric acid output and promotes healing and alleviates symptoms. Surgical removal of the tumor is possible in approximately 20% of all patients. Streptozocin is also used to reduce diarrhea and tumor mass. The drug Sandostatin has been found to be effective in controlling diarrhea and suppressing secretion of the hormones gastrin, insulin, glucagon and VIP by islet-cell tumors.
Pancreatic cholera (Verner-Morrison Syndrome) must be treated by replacing fluids and electrolytes lost in numerous watery stools. The tumor may be surgically removed in approximately 50% of the cases. Streptozocin may also be administered to reduce diarrhea and tumor mass. Some individuals may respond to a corticosteroid drug such as Prednisone. Sandostatin may be administered for severe diarrhea and to reduce elevated VIP levels produced by islet-cell tumors.
Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.
For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:
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REVIEW ARTICLES Menack MJ, et al. Laparoscopic sonography of the biliary tree and pancreas. Surg Clin North Am. 2000;80:1151-70.
Dolan JP, et al. Occult insulinoma. Br J Surg. 2000;87:385-87.
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JOURNAL ARTICLES Anderson MA, et al. Endoscopic ultrasound is highly accurate and directs management in patients with neuroendocrine tumors of the pancreas. Am J Gastroenterol. 2000;95:2271-77.
Berends FJ, et al. Laparoscopic detection and resection of insulinomas. Surgery. 2000;128:386-91.
Lam KY, et al. Telomerase activity in pancreatic endocrine tumours: a potential marker for malignancy. Mol Pathol. 2000;53:133-36.
Ichikawa T, et al. Islet cell tumor of the pancreas: biphasic CT versus MR imaging in tumor detection. Radiology. 2000;216:163-71.
American Cancer Society, Inc. 1599 Clifton Road NE Atlanta, GA 30329 USA Tel: (404)320-3333 Tel: (800)227-2345 Internet: http://www.cancer.org
NIH/National Digestive Diseases Information Clearinghouse 2 Information Way Bethesda, MD 20892-3570 Tel: (301)654-3810 Fax: (301)907-8906 Tel: (800)891-5389 Email: nddic@info.niddk.nih.gov Internet: http://www.niddk.nih.gov
MUMS (Mothers United for Moral Support, Inc) National Parent-to-Parent Network 150 Custer Court Green Bay, WI 54301-1243 USA Tel: (920)336-5333 Fax: (920)339-0995 Tel: (877)336-5333 Email: mums@netnet.net Internet: http://www.netnet.net/mums/
Genetic and Rare Diseases (GARD) Information Center PO Box 8126 Gaithersburg, MD 20898-8126 Tel: (301)519-3194 Fax: (240)632-9164 Tel: (888)205-2311 TDD: (888)205-3223 Email: gardinfo@nih.gov Internet: http://www.genome.gov/10000409
Cancer.Net American Society of Clinical Oncology 2318 Mill Road Suite 800 Alexandria, VA 22314 Tel: (571)483-1780 Fax: (571)366-9537 Tel: (888)651-3038 Email: contactus@cancer.net Internet: http://www.cancer.net/patient
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