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Pancreatic cancer is a disease in which normal cells in the pancreas stop working correctly and grow uncontrollably. These cancerous cells can build up and form a mass called a tumor. As it grows, a pancreatic tumor can affect the function of the pancreas, grow into nearby blood vessels and organs, and eventually metastasize (spread) to other parts of the body.
About the pancreas
The pancreas is a pear-shaped gland located in the abdomen between the stomach and the spine. It is about six inches in length and is made up of two major components:
- The exocrine component, made up of ducts and acini (small sacs on the end of the ducts), makes enzymes (specialized proteins) that are released into the small intestine to help the body digest and break down food, particularly fats.
- The endocrine component of the pancreas is made up of specialized cells lumped together in different locations within this part of the pancreas, called islets of Langerhans. These cells make specific hormones, most importantly insulin, the substance that helps control the amount of sugar in the blood.
There are several types of pancreatic cancer, depending on whether the cancer began in the exocrine or endocrine component. In addition, about 4% of pancreatic cancers are lymphomas or cannot be classified as a specific type.
Exocrine tumors. These are the most common type of pancreatic cancer. About 95% of people with pancreatic cancer have adenocarcinoma, which starts in gland cells. These tumors usually start in the ducts of the pancreas, called ductal adenocarcinoma. Much less commonly, if the tumor begins in the acini, it is called acinar adenocarcinoma.
An increasingly common diagnosis is called intraductal papillary mucinous neoplasm (IPMN). An IPMN is a tumor that grows within the ducts of the pancreas and makes a thick fluid called mucin. IPMN is not cancerous when it begins, but could become cancerous if not treated. Sometimes, an IPMN has already become cancer by the time it is diagnosed.
Much rarer types of exocrine pancreatic tumors include: acinar cell carcinoma, adenosquamous carcinoma, colloid carcinoma, giant cell tumor, hepatoid carcinoma, mucinous cystic neoplasms, pancreatoblastoma, serous cystadenoma, signet ring cell carcinoma, solid and pseudopapillary tumors, squamous cell carcinoma, and undifferentiated carcinoma.
Endocrine tumors. These are also called islet cell tumors or pancreatic neuroendocrine tumors (PNETs). They are much less common than exocrine tumors, making up about 1% of pancreatic cancers. A pancreatic neuroendocrine tumor can be functioning, meaning it makes hormones, or nonfunctioning, meaning it doesn’t make hormones. A functioning neuroendocrine tumor is named based on the hormone the cells normally make:
Looking for More of an Overview?
If you would like additional introductory information, explore these related items. Please note these links take you to other sections on Cancer.Net:
- ASCO Answers Fact Sheet: Read a one-page fact sheet (available in PDF) that offers an easy-to-print introduction to this type of cancer.
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- Cancer.Net En Español: Read about pancreatic cancer in Spanish. Infórmase sobre cancer pancreático en español.
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