What is a carcinoid tumor (neuroendocrine tumor)?

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Last updated: March 25, 2025View editorial policy

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From the Guidelines

Carcinoid tumors are well-differentiated neuroendocrine tumors that include low- and intermediate-grade malignant tumors, and are typically characterized by slow growth and potential to produce hormones, with treatment options including surgical removal, somatostatin analogs, and other therapies to manage symptoms and disease progression. The diagnosis of carcinoid tumors often involves a combination of imaging studies, such as contrast CT scans, and pathology examination to correctly classify the tumor [1]. Key characteristics of carcinoid tumors include:

  • Well-differentiated neuroendocrine tumors
  • Low- and intermediate-grade malignant tumors
  • Potential to produce hormones, leading to symptoms such as flushing, diarrhea, and wheezing
  • Slow growth, with potential for metastasis Treatment options for carcinoid tumors depend on the stage and location of the tumor, as well as the presence of symptoms, and may include:
  • Surgical removal of the tumor, which is often curative for localized disease
  • Somatostatin analogs, such as octreotide or lanreotide, to control symptoms of carcinoid syndrome
  • Targeted therapies, such as everolimus, for progressive disease
  • Liver-directed therapies, such as radiofrequency ablation or embolization, for hepatic metastases
  • Peptide receptor radionuclide therapy (PRRT) with lutetium-177 dotatate for progressive disease Regular monitoring with biomarkers, such as 5-HIAA urine tests and chromogranin A blood tests, as well as imaging studies, is essential for tracking disease progression [1]. It is also important for patients to avoid triggers that may precipitate carcinoid syndrome symptoms, such as alcohol, spicy foods, and certain cheeses [1]. Overall, the management of carcinoid tumors requires a comprehensive approach that takes into account the unique characteristics of the tumor, as well as the individual needs and circumstances of the patient.

From the Research

Definition and Characteristics of Carcinoid Tumors

  • Carcinoid tumors are neuroendocrine neoplasms, primarily of the gastrointestinal tract 2.
  • They belong to the family of neuroendocrine tumors, which are usually slow growing with distinct biological and clinical characteristics 3.
  • The incidence of these tumors is approximately 2.5 in 100,000 people per year 3.

Diagnosis and Detection

  • Carcinoid tumors often present with vague, nonspecific symptoms, making diagnosis challenging 2.
  • Determination of the histopathology of carcinoid tumors is of utmost importance and involves specific immunohistochemical staining for chromogranin A, synaptophysin, serotonin, and gastrin 3.
  • Localization procedures include computerized tomography, ultrasound, magnetic resonance imaging, somatostatin receptor scintigraphy, and positron emission tomography 4, 3.
  • Plasma chromogranin A levels and U-5-HIAA should be determined in patients with symptoms that might be connected to a neuroendocrine tumor 4.

Treatment and Management

  • Surgery remains the cornerstone of treatment and provides the only chance of a cure 3.
  • Other treatments include radiofrequency ablation, laser treatment, chemoembolization, and biological treatment with somatostatin analogs and interferon-alpha 3.
  • Combination regimens, such as cisplatin, etoposide, streptozotocin, and 5-fluorouracil, should be reserved for treatment of highly proliferating tumors 3.
  • Follow-up examinations are crucial in patients with carcinoid tumors, as they are at increased risk of developing other malignancies and recurrence of the tumor 2, 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Carcinoid tumors: what should increase our suspicion?

Cleveland Clinic journal of medicine, 2008

Research

Diagnosis and treatment of carcinoid tumors.

Expert review of anticancer therapy, 2003

Research

Carcinoid tumours.

Bailliere's clinical gastroenterology, 1996

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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