Carcinoid (Neuroendocrine) Tumors: The Basics

Author: OncoLink Team
Last Reviewed: June 28, 2022

Carcinoid tumors are caused by neuroendocrine cells growing out of control. Neuroendocrine cells act as both nerve and endocrine cells. As the number of cells grows, they form into a tumor. There are many types of neuroendocrine tumors and carcinoid is one of them. Carcinoid tumors are categorized into the three areas that they are found:

  • Foregut: lungs and stomach.
  • Midgut: small intestine, appendix, and the beginning of the large bowel.
  • Hindgut: end of the large bowel, rectum, and organs of the genitourinary tract.

Carcinoid cancer that has spread from the organ it started into another part of the body is called metastatic cancer.


Carcinoid tumors are found more in women than men, more often in people over age 60. It is more commonly found in the African American population. There are also a number of genetic syndromes associated with carcinoid tumors:

  • Multiple endocrine neoplasia type 1 (MEN 1).
  • Zollinger-Ellison Syndrome on its own or as part of MEN type 1.
  • Von Hippel-Lindau syndrome.


There are no specific screening tests for carcinoid tumors at this time.

Signs of Carcinoid Tumors

The early stages of carcinoid tumors may not have any signs. If a person does have signs, they will differ based on the organ being affected. Tumors in the small intestine can cause an obstruction and intestinal bleeding, colon tumors can cause intestinal bleeding, and those in the rectum can cause rectal bleeding and pain.

Carcinoid syndrome is a pattern of symptoms caused by the release of certain substances from the tumor. This release can be caused by foods high in tyramine (blue cheese and chocolate) and those that have ethanol (wine and beer). The signs of carcinoid syndrome are:

  • Flushing and telangiectasia (collections of blood vessels, purple in color, and often found on the face).
  • Diarrhea.
  • Rapid heartbeat.
  • Bronchospasm (closing off of the airways).
  • Pellagra (dry scaly skin, dry, cracked skin at the edges of the mouth, swollen tongue, diarrhea, and mental confusion.
  • Right-sided heart disease or failure.

Diagnosis of Carcinoid Tumors

When your healthcare providers think you may have a carcinoid tumor, they will order tests. Here are some of the tests

  • Urine tests.
  • Blood tests.
  • Epinephrine provocation test in which a provider tries to induce the signs of carcinoid syndrome using intravenous (IV) epinephrine.
  • Imaging tests and octreotide scans.

Staging Carcinoid Tumors

To guide treatment, carcinoid cancer is "staged" by location. They are also classified:

  • Localized: the tumor has not spread beyond the wall of the organ or place it started.
  • Regional: the tumor has spread beyond the organ to nearby tissues and lymph nodes.
  • Metastatic: the tumor has spread to distant organs and tissues.


The type of treatment used depends on where the cancer is and the person’s health. Often, the treatment of choice is surgery to remove the tumor. Other treatments are:

  • Radiation therapy, the use of high energy x-rays to kill cancer cells, can be used to treat metastases.
  • Chemotherapy, the use of medication to kill cancer cells, can be used to treat metastases. Chemoembolization can be used to treat cancer in the liver.
  • Medications can be used to control the issues related to carcinoid syndrome and to manage heart damage.

This article is a basic guide to carcinoid tumors. You can learn more about your type of carcinoid tumor and treatment by using the link below.

Carcinoid (Neuroendocrine) Tumors: Staging and Treatment

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