Neuroendocrine tumors are cancers that begin in specialized cells called neuroendocrine cells. Neuroendocrine cells have traits similar to those of nerve cells and hormone-producing cells.
Neuroendocrine tumors are rare and can occur anywhere in the body. Most neuroendocrine tumors occur in the lungs, appendix, small intestine, rectum and pancreas.
There are many types of neuroendocrine tumors. Some grow slowly and some grow very quickly. Some neuroendocrine tumors produce excess hormones (functional neuroendocrine tumors). Others don't release hormones or don't release enough to cause symptoms (nonfunctional neuroendocrine tumors).
Diagnosis and treatment of neuroendocrine tumors depend on the type of tumor, its location, whether it produces excess hormones, how aggressive it is and whether it has spread to other parts of the body.
Products & Services
Neuroendocrine tumors don't always cause signs and symptoms at first. The symptoms you might experience depend on the location of your tumor and whether it produces excess hormones.
In general, neuroendocrine tumor signs and symptoms might include:
- Pain from a growing tumor
- A growing lump you can feel under the skin
- Feeling unusually tired
- Losing weight without trying
Neuroendocrine tumors that produce excess hormones (functional tumors) might cause:
- Skin flushing
- Frequent urination
- Increased thirst
- Skin rash
When to see a doctor
Make an appointment with your doctor if you have any persistent signs and symptoms that worry you.
The exact cause of neuroendocrine tumors isn't known. These cancers begin in neuroendocrine cells that have traits similar to those of nerve cells and hormone-producing cells. Neuroendocrine cells are found throughout your body.
Neuroendocrine tumors begin when neuroendocrine cells develop changes (mutations) in their DNA. The DNA inside a cell contains the instructions that tell the cell what to do. The changes tell the neuroendocrine cells to multiply rapidly and form a tumor.
Some neuroendocrine tumors grow very slowly. Others are aggressive cancers that invade and destroy normal body tissue or spread (metastasize) to other parts of the body.
The risk of neuroendocrine tumors is higher in people who inherit genetic syndromes that increase the risk of cancer. Examples include:
- Multiple endocrine neoplasia, type 1 (MEN 1)
- Multiple endocrine neoplasia, type 2 (MEN 2)
- Von Hippel-Lindau disease
- Tuberous sclerosis
Get Mayo Clinic cancer expertise delivered to your inbox.
Subscribe for free and receive an in-depth guide to coping
with cancer, plus helpful information on how to get a second opinion. You can unsubscribe at any
ErrorEmail field is required
ErrorInclude a valid email address
To provide you with the most relevant and helpful information, and understand which
information is beneficial, we may combine your email and website usage information with
other information we have about you. If you are a Mayo Clinic patient, this could
include protected health information. If we combine this information with your protected
health information, we will treat all of that information as protected health
information and will only use or disclose that information as set forth in our notice of
privacy practices. You may opt-out of email communications at any time by clicking on
the unsubscribe link in the e-mail.
Thank you for subscribing
Your in-depth coping with cancer guide will be in your inbox shortly. You will also
receive emails from Mayo Clinic on the latest about cancer news, research, and care.
If you don’t receive our email within 5 minutes, check your SPAM folder, then contact us
Sorry something went wrong with your subscription
Please, try again in a couple of minutes