Carcinoid Syndrome

Syndrome caused by serotonin and other vasoactive substances released from neuroendocrine tumors.

Written by: Saygı Hospital Health Guide Editorial Board

Last updated: June 10, 2026

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 Endokrinoloji department. Book Appointment →

What is Carcinoid Syndrome?

Carcinoid syndrome is a clinical picture caused by the systemic effects of vasoactive substances such as serotonin, bradykinin and tachykinins secreted by metastatic neuroendocrine tumors (NETs) often originating from the small bowel. Liver metastasis is usually required for the syndrome to manifest.

Patients may present with facial flushing, watery diarrhea, cramping, bronchospasm, hypotension, right-sided heart failure (carcinoid heart disease) and pellagra-like skin changes. A carcinoid crisis can present with severe hemodynamic compromise during anesthesia or interventions.

Diagnosis uses 24-hour urinary 5-HIAA, chromogranin A and imaging modalities (somatostatin receptor PET, MR). Treatment includes somatostatin analogs, telotristat, PRRT (Lu-177 DOTATATE), interferon and surgery/RFA.

Symptoms

Episodes of flushing

Watery diarrhea

Abdominal cramping

Bronchospasm

Right-sided heart failure

Pellagra-like skin lesions

Weight loss

Risk Factors

Small bowel or appendiceal NET

Liver metastasis

Unresected tumor

Genetic syndromes (MEN1)

Older age

Delayed diagnosis

History of carcinoid heart disease

When to See a Doctor?

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

Recurrent flushing plus diarrhea
Signs of right heart failure
New symptoms in known NET
Unexplained bronchospasm
Suspicion of carcinoid crisis
Suspected liver metastasis

Treatment Methods

Somatostatin analog (octreotide, lanreotide)

Telotristat for diarrhea

PRRT (Lu-177 DOTATATE)

Surgical debulking

Hepatic transarterial embolization

Carcinoid heart surgery

Nutritional support (niacin)

Multidisciplinary team

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.

Learn About Endokrinoloji Department

Let us help you

You can make an appointment with our specialists or contact us for your concerns.

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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.