What are the clinical presentations and complications of Carcinoid (Neuroendocrine) tumors of the colorectum?

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Last updated: February 19, 2025View editorial policy

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From the Guidelines

Carcinoid colorectal cancer typically presents with vague symptoms, including abdominal pain, changes in bowel habits, and unexplained weight loss, and can lead to serious complications if left untreated, such as bowel obstruction, metastasis, and carcinoid heart disease. Here's a concise overview of the clinical presentations and complications:

Presentation

  • Abdominal pain or discomfort
  • Changes in bowel habits (diarrhea or constipation)
  • Rectal bleeding or blood in stool
  • Unexplained weight loss
  • Fatigue
  • In some cases, carcinoid syndrome (flushing, diarrhea, wheezing) 1

Complications

  • Bowel obstruction
  • Metastasis, commonly to the liver 1
  • Carcinoid heart disease
  • Carcinoid crisis (severe form of carcinoid syndrome)
  • Malnutrition
  • Anemia

Early detection through screening colonoscopies is crucial for better outcomes, and treatment typically involves surgical resection of the tumor, followed by targeted therapies or chemotherapy if metastasis has occurred. Somatostatin analogs like octreotide may be used to manage carcinoid syndrome symptoms, with standard doses of octreotide LAR being 20 to 30 mg intramuscularly every 4 weeks 1. Regular follow-up and monitoring are essential due to the slow-growing nature of these tumors and the potential for late recurrence or metastasis. In cases of limited hepatic metastases, resection of the primary tumor and metastases can be performed, with a reported 10-year overall survival rate of 50.4% 1.

From the Research

Clinical Presentations of Carcinoid (Neuroendocrine) Tumors of the Colorectum

  • The most frequent symptoms or signs encountered in patients with carcinoid tumors of the colon are abdominal pain, anorexia or weight loss, diarrhea, abdominal tenderness, palpable abdominal mass, and rectal bleeding 2.
  • No carcinoid syndrome was noted in the study of 23 patients with colonic carcinoids 2.
  • The clinical presentation of patients with carcinoid tumors of the colon may include symptoms such as abdominal pain, diarrhea, weakness, and anorexia, which occur late in the course of the disease 3.
  • Rectal bleeding, weight loss, abdominal pain, diarrhea, and constipation are also common symptoms associated with colorectal cancer, which may be related to carcinoid tumors of the colorectum 4, 5.

Complications of Carcinoid (Neuroendocrine) Tumors of the Colorectum

  • Spreading of the disease to the liver and peritoneum was found in 2 (8.7%) patients who submitted to intestinal bypass 2.
  • Venous invasion and neural infiltration were both present in 5 (23.8%) patients with carcinoid tumors of the colon 2.
  • The tumors had penetrated the muscularis propria in all resected cases, indicating a high risk of complications and poor prognosis 2.
  • Carcinoid tumors of the colon are diagnosed late in the course of the disease and carry a bad prognosis, with a 2-year and 5-year actuarial survival of 34% and 26%, respectively 3.
  • Postoperative complications, metachronous metastases, and local recurrence are common causes of death in patients with carcinoid tumors of the colon 2.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Colon carcinoid tumors. A population-based study.

Diseases of the colon and rectum, 1994

Research

How does colorectal cancer present? Symptoms, duration, and clues to location.

The American journal of gastroenterology, 1999

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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