Carcinoid Tumor Symptoms

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Carcinoid tumors are rare, slow-growing neuroendocrine tumors (NETs) that can arise in several places throughout the body. Carcinoid tumors are believed to derive from neuroendocrine tumors that usually begin in the digestive tract (stomach, appendix, small intestine, duodenum, colon, and rectum) or in the lungs.

Fewer than 10% of people with carcinoid tumors have or develop symptoms. If you have a carcinoid tumor, you may have it for years and never know it. However, symptoms of carcinoid tumor are possible and depend on where it is located in the body and where chemicals are secreted in the bloodstream.

If the carcinoid tumor is located in the digestive tract, symptoms may include pain in the abdomen, nausea, vomiting, and constipation. However, if the carcinoid tumor is in the lungs, symptoms can include trouble breathing, chest pain, wheezing, and redness, or a feeling of warmth on the neck (skin flushing).

mid adult woman experiences various physical pain symptoms

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Frequent Symptoms

Common symptoms of gastrointestinal carcinoid tumor may include:

  • Abdominal pain
  • Nausea, vomiting, or constipation
  • Diarrhea
  • Rectal bleeding
  • Rectal pain

Common symptoms of respiratory carcinoid tumor may include:

  • Trouble breathing
  • Chest pain
  • Wheezing

Rare Symptoms

Although rare, if carcinoid tumors become advanced, they may develop into a condition called carcinoid syndrome. Carcinoid syndrome is believed to be caused be a release of certain chemicals like serotonin and hormones in the bloodstream. Rare symptoms include:

  • Redness or a feeling of warmth on the neck (skin flushing): The skin on your face and upper chest can feel hot and change color, from pink to purple. Flushing episodes may last from a few minutes to a few hours or longer.
  • Skin lesions on the face: Welts or spider-like veins, along with purplish discolored areas, may appear on the nose and upper lip.
  • Heart abnormalities: A rapid heartbeat or heart valve problems could be a sign of carcinoid syndrome.
  • Bowel obstruction: This occurs when a section of the small or large intestine becomes partially or completely blocked. Symptoms include abdominal pain, fevers, constipation, and vomiting. This can be a dangerous condition, potentially increasing the risk of a severe infection or a perforation (hole) in the intestine. 
  • Pellagra: This is a condition that occurs when a person develops a deficiency in vitamin B3 (niacin). A deficiency in niacin can result in rough scaly skin, diarrhea, and, in more serious cases, encephalopathy. If the condition is left untreated, it can lead to death.

Complications

Carcinoid cancers do not typically result in complications, but they can if the cancer has metastasized (spread) or if carcinoid syndrome develops. Although complications are not true symptoms and not everyone will experience them, knowledge of them may be lifesaving. Some possible complications of carcinoid tumor include:

  • Carcinoid crisis: This is a serious version of carcinoid syndrome. It happens when neuroendocrine tumors (NETs) make too many hormones and proteins that get released in the bloodstream. More often, this complication can occur spontaneously during stressful procedures, such as when under anesthesia and/or during tumor removal during surgery. It is believed these procedures can mimic a reaction of anaphylactic shock (severe allergic reaction), which poses a challenge for surgeons and anesthesiologists.
  • Cognitive impairment and psychiatric disorders: Studies have shown that carcinoid syndrome may be linked with cognitive impairment, including delayed verbal and visual memory. This is believed to be caused by reduced levels of serotonin in the brain. Studies have also shown that in rare cases, carcinoid syndrome causes aggressive behavior as a result of decreased levels of tryptophan (an essential amino acid) in the brain.
  • Cushing's syndrome: Some carcinoid tumors produce a hormone that causes the adrenal glands to make too much cortisol (a steroid). This can cause Cushing's syndrome.

Symptoms of Cushing's Syndrome

Symptoms of Cushing's syndrome include:

  • Weight gain
  • Muscle weakness
  • High blood sugar (even diabetes)
  • High blood pressure
  • Increased body and facial hair
  • A bulge of fat on the back of the neck
  • Skin changes like stretch marks (called striae)

Treatments for Cushing's syndrome may include surgery, radiation, chemotherapy, or cortisol-reducing medicines.

Serotonin

In some cases, treatments that reduce serotonin levels to control carcinoid syndrome have been linked to depression, anxiety, and trouble sleeping. This is due to a depletion and disturbance of natural serotonin levels in the brain. Therefore, it is important to report any notable psychological or mood changes to your doctor if you or someone you know has carcinoid syndrome.

When to See a Doctor

According to the National Institutes of Health (NIH), fewer than 10% of people with carcinoid tumors have or develop symptoms. If you have carcinoid tumor, you may have it for years and never know it. However, this statistic may vary based on the location of the tumor and when it is diagnosed by your healthcare provider. Since carcinoid cancers grow very slowly, they are usually not diagnosed until ages 55–65. It is therefore important to establish routine physical checkups with your doctor.

If you have symptoms that could indicate carcinoid tumor, be sure to talk to your doctor about them, particularly if you have a family history of the disease. Early carcinoid tumor diagnosis and treatment have long-term benefits, including a good prognosis and lower mortality rates, so don't hesitate or wait to bring up what you're experiencing.

Communicate With Your Doctor

After your diagnosis, it's important to let your doctor know about any changes or new symptoms you experience. Carcinoid tumors are slow growing, so the earlier the detection, the better. If small carcinoid tumors have not spread yet, surgery is the best way to remove them.

A Word From Verywell

Carcinoid cancer is relatively uncommon. Sometimes, it can be completely cured, but even when the condition is not curable, it can typically be managed and has a good prognosis. 

Often, people who have rare medical conditions can benefit from joining support groups. Because this type of cancer isn't common, you might not have a support group in your area. Therefore, consider finding a community online. Your medical team can provide you with information about reputable groups and associations.

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6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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