ON THIS PAGE: You will find some basic information about this disease and the parts of the body it may affect. This is the first page of Cancer.Net’s Guide to Endocrine Tumors. To see other pages, use the menu on the side of your screen. Think of that menu as a roadmap to this full guide.
About the endocrine system
The endocrine system is made up of cells that produce hormones. Hormones are chemical substances that are made by the body and carried through the bloodstream to have a specific regulatory effect on the activity of other organs or cells. For example, part of the pancreas is made up of specialized cells clustered together in islands within the organ, called islets of Langerhans. These cells make different types of hormones—the most important being insulin, which is a substance that helps control the amount of sugar in the blood.
Part of the endocrine system is the neuroendocrine system, which is made up of cells that are a cross between traditional endocrine cells (or hormone-producing cells) and nerve cells. Neuroendocrine cells are found throughout the body in organs such as the lungs and gastrointestinal tract. They perform specific functions, such as regulating the air and blood flow through the lungs and controlling the speed at which food is moved through the gastrointestinal tract.
About endocrine tumors
A tumor begins when normal cells in the body change and grow uncontrollably, forming a mass. A tumor can be cancerous or benign. A cancerous tumor is malignant, meaning it can spread to other parts of the body. A benign tumor means the tumor will not spread.
An endocrine tumor is a mass that affects the parts of the body that secrete hormones. Because an endocrine tumor starts in the cells that make hormones, the tumor itself can make hormones and cause serious illness.
There are several types of endocrine tumors. For more specific information on each type, select a name below:
- Adrenal gland tumor  (includes information on adenomas and adrenocortical carcinoma)
- Carcinoid tumors  (includes information on both lung and gastrointestinal carcinoid tumors)
- Islet cell tumor  (includes information on gastrinoma, insulinoma, glucagonoma, VIPoma, somatostatinoma, and nonfunctioning tumors)
- Neuroendocrine tumor  (includes information on Merkel cell cancer, pheochromocytoma, and neuroendocrine carcinoma)
- Thyroid cancer 
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