Neuroendocrine Tumors of the Pancreas

A neuroendocrine tumor of the pancreas develops in the islet cells, which are responsible for the production of hormones. Endocrine cancers occur much less frequently than adenocarcinomas: on average only one out every 100,000 people will develop a neuroendocrine tumor. In the United States, 2,500 people a year are diagnosed with some form of neuroendocrine tumor.

A neuroendocrine tumor is usually less aggressive than an adenocarcinoma, increasing the chances that the growth can be removed before metastasis — spreading to other organs. Depending on the individual growth, the cancer may cause excessive amounts of hormones to flood the body or may entirely shut down hormone production.

Non-Functioning Islet Cell Tumors

Non-functioning islet cell tumors account for sixty percent of all endocrine pancreas cancers. The abnormal cells stop producing hormones. As a result, the often-dramatic symptoms associated with other neuroendocrine tumors are not present, and the affected tissue can grow to large sizes before diagnosis is made. However, non-functioning islet cell cancers are less aggressive than adenocarcinomas and the chance is much higher that metastasis will not have occurred at the time of diagnosis. Symptoms are usually vague if they are even present, and include abdominal pain and jaundice.

Functioning Islet Cell Tumors

Functioning islet cell tumors differ from non-functioning growths in that they produce excessive amounts of hormones. This can lead to a wide range of symptoms, including stomach ulcers, diabetes, diarrhea, abnormal blood sugar levels, and skin rashes. Of the different varieties of functioning neuroendocrine tumors, insulinoma and gastrinoma are the most common.

Insulinoma and Blood Sugar Levels

Insulinoma affects insulin producing cells, resulting in the production of large amounts of insulin, which causes low blood sugar levels (hypoglycemia). Hypoglycemia can cause symptoms such as fatigue, hunger, weakness, tremors and confusion.

Definition of islet cell tumor: A mass of abnormal cells that forms in the endocrine (hormone-producing) tissues of the pancreas. Islet cell tumors may be benign (not cancer) or malignant (cancer).

Women develop insulinoma more often than men. In ninety percent of all cases the growths are benign and usually quite small in size. If the insulinoma is removed surgically, ninety percent of patients require no further treatment.

Gastrinoma and Stomach Ulcers

Sixty percent of gastrinomas (also known as Zollinger-Ellison Syndrome) are malignant and although slow growing, the vast majority have metastasized at the time of diagnosis. Gastrinomas affect islet cells that produce the digestive hormone gastrin. Recurring stomach ulcers, possibly accompanied by an almost constant need for ulcer medication, suggest the possibility of gastrinoma. Ulcer symptoms are treated with omeprazole (Prilosec, Losec).