Intestinal Carcinoid Tumor Clinical Presentation

Updated: Dec 20, 2021
  • Author: Rachel E Lewis, MD; Chief Editor: N Joseph Espat, MD, MS, FACS  more...
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Most intestinal carcinoids are asymptomatic, and their diagnosis is usually made incidentally or at autopsy. Presenting symptoms are due to either the size of the tumor or the secretion of biologically active peptides or amines into the bloodstream. Additionally, the presence of symptoms will vary depending on the location of the primary tumor (see Table 2).

Table 2. Presentation of Intestinal Carcinoids (Open Table in a new window)


Nonhormonal Symptoms




Pernicious anemia

Small intestine



Intestinal obstruction




Incidental finding






Weight loss







Constitutional symptoms, such as anorexia, weight loss, and fatigue, are common to the clinical presentation. They can be related to local or distant spread, which is present in up to 47.5% of patients at the time of diagnosis. [7] In such cases, the disease is typically estimated to have been present for more than 8 years before diagnosis. Early diagnosis is often difficult because the patient generally reports only vague abdominal symptoms or flushing.

Most patients complain of abdominal pain. Patients with carcinoid tumors are often misdiagnosed with irritable bowel syndrome or idiopathic flushing. Flushing can occur spontaneously without the carcinoid syndrome, and it is reported in approximately 2% of patients with small-intestine primary tumors.

Patients with midgut carcinoids frequently have symptoms for long periods (ie, 2-5 years or more) before a specific diagnosis is made. In this group of patients, early diagnosis can potentially lead to a cure by surgical resection of the primary tumor. The most common symptoms and signs of an intestinal carcinoid are abdominal pain, intermittent obstruction, and a palpable abdominal mass.

Obstruction usually occurs after invasion of the mesentery, and the resulting desmoplastic reaction with scarring and matting of small bowel loops, in turn, can produce a mass and intermittently obstruct the intestine. The clinical picture of recurrent intermittent intestinal obstruction should raise the suggestion of carcinoid tumor. Because this process is extraluminal, results of endoscopic examination may be normal approximately half the time.

Carcinoid Syndrome

The syndrome is characterized by hepatomegaly, diarrhea, and flushing in 80% of patients; right heart valvular disease in 50%; and asthma in 25%. Malabsorption and pellagra (ie, dementia, dermatitis, and diarrhea) are occasionally present and are thought to be caused by the excessive diversion of dietary tryptophan to serotonin.

Diarrhea is the most common feature of carcinoid syndrome, affecting 80% of patients. It is usually episodic, often occurring after meals. The diarrhea is due to elevated circulating levels of serotonin, which stimulate the secretion of small-bowel fluid and electrolytes and increase intestinal motility.

Asthma (25% of patients) is due to bronchoconstriction, which may be attributed to serotonin, bradykinin, or substance P elaborated by the carcinoid tumor. The treatment of asthma associated with carcinoid syndrome must be conducted very carefully because adrenergic drugs may cause the release of humoral agents from the tumor, resulting in status asthmaticus.


Physical Examination

Physical examination findings may be normal, and the patient may appear to be healthy.

Patients in carcinoid crises can have face, neck, and upper chest flushing lasting for hours to days. They can have hypotension, increased lacrimation, and fever and can be in moderate to severe distress. The typical patient is 61-66 years old and experiences flushing when performing a Valsalva maneuver.

Skin findings include facial telangiectasias, usually bimalar. Extremity rash is usually a finding in severe, uncontrolled, end-stage disease, thus implying niacin deficiency.

Examination of the lungs may reveal wheezing. Cardiac examination usually yields normal results, but with prolonged, uncontrolled serotonin secretion, patients may have evidence of tricuspid valve regurgitation and, less commonly, pulmonic stenosis.

The abdomen may be distended and nontender. Bowel sounds may be normal or high pitched. Hepatomegaly is possible.

Examination of the extremities may demonstrate bilateral lower extremity edema.