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Carcinoid Syndrome and Neuroendocrine Tumors

Clinical manifestations of neuroendocrine tumors secreting serotonin and other bioactive substances.

Written by: Saygı Hospital Health Guide Editorial Board
Last updated:

This content has been compiled by the Saygı Hospital Health Guide Editorial Board and is periodically reviewed by a specialist physician.

References (5)

This content is for informational purposes only and does not constitute medical advice. You can book an appointment at our Internal Medicine department. Book Appointment →

What is Carcinoid Syndrome and Neuroendocrine Tumors?

Carcinoid syndrome is a clinical syndrome that occurs when serotonin, histamine, tachykinins, and prostaglandins secreted by neuroendocrine tumors (NET) enter the systemic circulation. It usually becomes symptomatic when there is liver metastasis (when bypassing hepatic metabolism).

Neuroendocrine tumors can originate from the GI tract (most often small bowel and appendix), lung, pancreas, and rarely other organs. According to the WHO classification, they are graded as grade 1 (low), grade 2 (intermediate), and grade 3 (high).

Carcinoid heart disease (especially right-sided valve involvement — tricuspid regurgitation and pulmonary stenosis) develops in 20-50% of patients and is an important cause of morbidity.

Symptoms

Flushing (episodes of redness in the face and neck)
Secretory diarrhea (watery, frequent diarrhea)
Bronchospasm (wheezing)
Carcinoid crisis (severe hypotension/hypertension during anesthesia/surgery) → EMERGENCY
Right heart failure findings (in carcinoid heart disease)

Risk Factors

Neuroendocrine tumor with liver metastasis
Small bowel primary NET (highest risk of carcinoid syndrome)
High tumor burden (high 5-HIAA level)
Surgery or anesthesia (carcinoid crisis trigger)
Alcohol, stress, exercise (flush triggers)

When to See a Doctor?

If you experience any of the following symptoms, seek medical attention promptly:

  • If there are recurrent flushing + diarrhea episodes
  • If unexplained right heart failure develops
  • Carcinoid crisis findings (severe flushing + hemodynamic instability) → EMERGENCY
  • If elevated urinary 5-HIAA is detected

Treatment Methods

01
Somatostatin analogs (octreotide LAR or lanreotide — symptom control + antiproliferative)
02
Telotristat ethyl (oral tryptophan hydroxylase inhibitor — in refractory diarrhea)
03
PRRT (Peptide Receptor Radionuclide Therapy — 177Lu-DOTATATE)
04
Surgical resection (primary tumor + liver metastasis debulking when possible)
05
Carcinoid crisis prophylaxis: Preoperative IV octreotide infusion
06
Cardiac valve surgery (if needed in carcinoid heart disease)

Which Department to Visit?

You can visit our Endokrinoloji department for these complaints. Our specialist physicians will create the most suitable treatment plan for you.

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Let us help you

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Health Disclaimer: The information on this page is prepared for general informational purposes only. It does not replace medical diagnosis and treatment. Please consult your physician for your complaints. Saygı Hospital does not accept responsibility for actions taken based on the information on this page.