Diagnosis of Carcinoid Tumors

Signs and Symptoms of Carcinoid Tumors

Carcinoid tumors are slow-growing tumors and most do not cause symptoms until they interfere with daily function or metastasize. Symptoms are often associated with the site of tumor origin and reflect the tumor obstructing organs involved in normal body function but may be less specific if related to carcinoid syndrome

Symptoms for some specific tumors include:

Foregut carcinoid tumors

Pulmonary Carcinoids (lung)

Pulmonary carcinoids are also referred to as bronchial carcinoids. The most common presentation is that of a patient over the age of 50 who presents with a pulmonary mass. Carcinoid lung tumors grow slowly and are more likely to be metastatic if they are large and cells are undifferentiated in appearance. It may be difficult to differentiate these tumors from small cell carcinomas. A syndrome characterized by flushing and wheezing may occur in a subset of patients (carcinoid syndrome).

Symptoms of pulmonary carcinoids are usually related to bronchial obstruction and may include:

  • Cough
  • Bloody sputum (hemoptysis)
  • Wheezing or asthma-like symptoms
  • Pneumonia unresponsive to treatment

Other symptoms may include:

  • Tremor
  • Lacrimation (tearing of the eye)
  • Anxiety
  • Hypotension (low blood pressure)

If the carcinoid tumor secretes ACTH (adrenocorticotropic hormone), additional symptoms may include:

  • Weight gain
  • Increased facial and/or body hair

More serious symptoms may include:

  • Pulmonary edema (fluid in the lungs)
  • Cushing syndrome (a disease caused by the overproduction of the hormone cortisol by the adrenal glands)
  • Hemoptysis (vomiting blood)

Up to 80% of lung carcinoid tumors are located centrally in or near central airways and 20% are located peripherally. Lung tumors are less likely than GI tract tumors to release hormone-like substances into the blood.

Pancreas

Pancreatic carcinoid tumors can produce several different substances (e.g., gastrin, insulin) and symptom presentation is usually related to the effects of the prevalent substance that is produced.

Thymus Gland

This carcinoid is seen primarily in men. Symptoms may be due to compression and include chest pain and indigestion.

Gastric Carcinoids

There are three types of gastric (stomach) carcinoid tumors. Those associated with gastrinemia (elevated levels of the hormone gastrin which is produced by the carcinoid cells lining the mucous membranes of the stomach) have a lower malignant potential than those that are not. The categories of gastric tumors include:

  • Type 1 gastric carcinoids are associated with chronic atrophic gastritis (chronic inflammation of the stomach that causes the disintegration of the mucous membranes in the stomach and a reduction in the number of functioning stomach cells) and pernicious anemia (severe anemia caused inadequate production of a substance that is needed for absorption of vitamin B12) and generally is seen in the elderly population. Type 1 gastric carcinoid tumors are characterized by hypergastrinemia (elevation of the levels of the hormone gastrin).

  • Type 2 gastric carcinoids are generally seen in patients with MEN I or Zollinger-Ellison Syndrome (ZES) and also involve high levels of gastrin. Although overall these tumors are uncommon, they are seen in up to one-third (33%) of patients with either ZES or MEN I. The majority of these tumors are not metastatic.

  • Type 3 gastric carcinoids are called sporadic tumors and are the most malignant of the gastric tumors. Between 15% to 25% of gastric carcinoids are sporadic and are not associated with elevated levels of gastrin. They usually exhibit aggressive growth and tend to be already metastatic at the time of diagnosis. Because of the aggressive nature of this tumor, treatment usually consists of radical gastrectomy (surgical removal of the stomach).

Presenting symptoms of gastric carcinoid tumors may include:

  • Peptic ulcer disease (PUD),
  • Bleeding
  • Obstruction of gastric outlet
  • Pain

Most gastric carcinoid tumors produce gastrin and histamines but not serotonin.

Midgut Carcinoid Tumors

Small Intestines

The most common site for carcinoid tumors in men is the small intestines. These tumors are often asymptomatic (without symptoms), slow growing, and frequently are not discovered until they are locally advanced or metastatic. Most people remain asymptomatic if the tumors are very small (less than 2 cm.). Carcinoid syndrome associated with the midgut carcinoid tumors of the small intestines will generally only develop in those patients with hepatic (liver) metastasis.

The most common symptoms associated with small intestinal carcinoid tumors include:

  • Periodic abdominal pain
  • Weight loss
  • Small bowel obstruction
Appendiceal Carcinoids

The appendix is the most common site for carcinoid tumors in women. Up to 80% of appendiceal carcinoids (carcinoid tumors of the appendix) are discovered incidentally during an appendectomy. Therefore, the majority of patients will be asymptomatic unless there is a coincident appendicitis. In general the prognosis is excellent for tumors less than 2 cm. in size as they are unlikely to metastasize. The risk of metastasis is greater in appendiceal tumors larger than 2 cm.

Hindgut Carcinoid Tumors

Colon

The typical presentation includes:

  • Pain associated with obstruction
  • GI bleeding (not common)

Most carcinoid tumors of the colon are found on the right side and are detected either at routine colonoscopy or evaluation for abdominal pain or weight loss.

Rectum

In most cases these tumors are discovered during colonoscopy and are asymptomatic. Larger tumors (i.e., greater than 2 cm) are more likely to develop metastases. The most common symptom, if present, is rectal bleeding.