Carcinoid Tumor


  • Anatomic Sites of Prevalence in the US
    • 55%: originate in gastrointestinal tract
      • Most common gastrointestinal site: ileum
      • Second most common gastrointestinal site: rectum
    • 30%: originate in lungs/airways

Pathology and Physiology

  • Pathology: well-differentiated neuroendocrine tumor originating in the gastrointestinal tract, lungs, kidneys (rarely), or ovaries (rarely)
    • Carcinoid tumors arise from neuroendocrine (enterochromaffin) cells of the aerodigestive tract
      • “Enterochromaffin” refers to the ability to stain with potassium chromate (chromaffin), a characteristic of cells that contain serotonin

Clinical Manifestations of Foregut Carcinoid Tumors

Gastric Carcinoid Tumor

  • Type I Gastric Carcinoid: account for 70-80% of gastric carcinoids
    • Abdominal Pain (see Abdominal Pain, [[Abdominal Pain]])
    • Chronic Atrophic Gastritis
    • Pernicious Anemia
  • Type II Gastric Carcinoid: account for 5% of gastric carcinoids
    • Occur in association with gastrinomas (Zollinger-Ellison syndrome) usually with multiple endocrine neoplasia (MEN) type I
  • Type III Gastric Carcinoid: account for 20% of gastric carcinoids
    • Sporadic carcinoids (occur in the absence of chronic atrophic gastritis or Zollinger-Ellison syndrome or MEN-I

Bronchial Carcinoid Tumor

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Clinical Manifestations of Midgut Carcinoid Tumors

Appendiceal Carcinoid Tumor

  • Asymptomatic: usually
  • Obstruction

Jejuno-Ileal Carcinoid Tumor

  • Abdominal Pain (see Abdominal Pain, [[Abdominal Pain]]): most common symptom
    • Mechanisms
      • Intussusception
      • Mechanical Effect of the Carcinoid Tumor
      • Mesenteric Ischemia
  • Asymptomatic
  • Intermittent Small Bowel Obstruction (SBO) (see Small Bowel Obstruction, [[Small Bowel Obstruction]])

Clinical Manifestations of Hindgut Carcinoid Tumors

Colonic Carcinoid Tumor

Rectal Carcinoid Tumor

  • Asymptomatic: usually
  • Incidental Diagnosis on Rectal Exam

Genitourinary Carcinoid Tumor

  • Renal Carcinoid
  • Testicular Carcinoid

Clinical Manifestations of Ovarian Carcinoid Tumors

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  • Metastatic: xxx

Sites of Metastases from Carcinoid Tumors

  • Hepatic Metastases: characteristic site of metastasis, regardless of site of origin
    • Clinical Manifestations
      • Carcinoid Syndrome (see Carcinoid Syndrome, [[Carcinoid Syndrome]]): flushing, diarrhea
      • Hepatomegaly (see Hepatomegaly, [[Hepatomegaly]]
      • Hepatic Dysfunction: jaundice, right upper quadrant pain, early satiety, etc
  • Mesenteric/Peritoneal Metastases: may occur with midgut carcinoid tumors
  • Bone Metastases (Usually in the Axial Skeleton): occur late in course
  • Other Sites of Metastasis
    • Breast
    • Ovary
    • Retroperitoneal Lymph Nodes
    • Supraclavicular Lymph Nodes


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