Epidemiology

• 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

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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

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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

• xxxx

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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]])

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Clinical Manifestations of Hindgut Carcinoid Tumors

Colonic Carcinoid Tumor

• Abdominal Pain (see Abdominal Pain, [[Abdominal Pain]])
• Anorexia (see Anorexia, [[Anorexia]])
• Diarrhea (see Diarrhea, [[Diarrhea]])
• Weight Loss (see Weight Loss, [[Weight Loss]])

Rectal Carcinoid Tumor

• Asymptomatic: usually
• Incidental Diagnosis on Rectal Exam

Genitourinary Carcinoid Tumor

• Renal Carcinoid
• Testicular Carcinoid

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Clinical Manifestations of Ovarian Carcinoid Tumors

• Primary: xxx
• Metastatic: xxx

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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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Treatment

• xxx

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References

• xxx