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pancreatic
Neuroendocrine Tumors
Some rare forms of pancreatic cancer
form from the abnormal growth of hormone-producing cells in the pancreas
called islet cells. These tumors are known as pancreatic neuroendocrine
tumors (pancreaticNETs or PNETs), pancreatic endocrine tumors or islet
cell tumors.
Islet cells are the endocrine cells in the pancreas that produce and secrete
the hormones insulin, glucagon and somatostatin into the bloodstream.
Insulin and glucagon are the two main pancreatic hormones. Insulin lowers
blood sugar levels while glucagon raises blood sugar levels. Together,
these two main hormones work to maintain the proper level of sugar in
the blood. Somatostatin regulates the levels of a variety of other hormones
in the blood.
Pancreatic neuroendocrine tumors account for less than 5% of all pancreatic
tumors. They may be benign or malignant and they tend to grow slower than
exocrine tumors. Pancreatic neuroendocrine tumors are either functional
(produce hormones) or nonfunctional (produce no hormones). Most functional
neuroendocrine tumors are benign. However, 90% of nonfunctional neuroendocrine
tumors are cancerous. The following table describes the different types
of pancreatic neuroendocrine tumors.
| Types |
Description |
| Gastrinoma (Zollinger-Ellison Syndrome) |
Gastrinomas overproduce gastrin. Most are malignant
or have the ability to become malignant. When this tumor is inherited
as part of a genetic syndrome called Multiple Endocrine Neoplasia
Type 1 (MEN1) (see below), multiple tumors may be found in the head
of the pancreas and/or the duodenum. |
| Glucagonoma |
Glucagonomas
overproduce glucagon. They are usually large, often metastasize
and about 70% are malignant. They are commonly found in the body
and tail of the pancreas. |
| Insulinoma |
Insulinomas overproduce insulin. They are the most
common pancreatic neuroendocrine tumors. They tend to be small and
hard to find. Most of them are benign. |
| Nonfunctional Islet Cell Tumor |
Nonfunctional islet cell tumors are usually malignant.
They are hard to detect. |
| Somatostatinoma |
Somatostatinomas overproduce somatostatin. They
are extremely rare and usually very large. They can occur anywhere
in the pancreas and in the duodenum. They vary in their potential
to become malignant. |
| Vasoactive Intestinal Peptide-Releasing Tumor
(VIPoma or Verner-Morrison Syndrome) |
VIPomas overproduce vasoactive intestinal peptide
(VIP). These tumors are usually located in the body and tail of the
pancreas. Two-thirds of VIPomas are found in women. The syndrome is
also known as Watery Diarrhea and Hypokalemia Achlorhydria (WDHA)
Syndrome. |
Multiple Endocrine Neoplasia
Type-1 (MEN1)
MEN1 (also known as Wermer Syndrome) is a hereditary syndrome that causes
multiple tumors in the parathyroid and pituitary glands, and the pancreas.
It occurs when tumors are found in at least two of the three endocrine
glands mentioned above. About 30-75% of people with MEN1 will develop
pancreatic neuroendocrine tumors. Gastrinomas are the most common pancreatic
neuroendocrine tumors in individuals with MEN1. The second most common
are insulinomas. The tumors in the pancreas may be malignant and generally
appear in individuals in their 30’s and 40’s.
The information
and services provided by the Pancreatic Cancer Action Network, Inc. are
for informational purposes only. The information and services are
not intended to be substitutes for professional medical advice, diagnosis
or treatment. If you are ill, or suspect that you are ill, see a
doctor immediately! The Pancreatic Cancer Action Network does not
recommend nor endorse any specific physicians, products or treatments
even though they may be mentioned on this site. 111230 |
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