Islet cell tumors arise in the Isle of Langerhans, a cluster of specialized cells in the part of the pancreas that produces hormones (the endocrine pancreas). Only about 5 percent of pancreatic cancers arise from the islet cells; most pancreatic cancers develop in the part of the pancreas that secretes digestive juices (the exocrine pancreas).
Most islet cell tumors are one of two types:
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Insulinomas
Pancreatic tumors that produce too much insulin, causing your body to store sugar instead of burning it as energy. This causes hypoglycemia, in which too little sugar is in your blood. Many insulinomas are either benign or slow-growing.
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Gastrinomas
Pancreatic tumors that produce too much gastrin, a hormone that prompts acid production in the stomach. Patients with gastrinomas often develop stomach ulcers because of too much acid. Many gastrinomas are malignant.
Symptoms of islet cell cancers include pain in your stomach or abdomen, diarrhea, chronic fatigue, fainting, and/or unexplained weight gain. Islet cell cancers are usually diagnosed using blood and urine tests (to check levels of hormones) and x-rays or other special imaging tests. Treatment usually includes surgery and may also include hormone therapy or chemotherapy, alone or in combination, and depends on whether the cancer has spread beyond the pancreas. Symptoms of hormonal imbalance may need to be treated in addition to treatment of the tumor itself.
