II. Epidemiology
- Prevalence: 1-2 per 100,000
- Age at presentation: 50-60 years
III. Pathophysiology
- Carcinoid Tumor originates from Gastrointestinal Tract
- Malignant neoplasms of enterochromaffin cells
- Metastases
- Most common sources of metastases
- Colon (more than two thirds at diagnosis)
- Small Intestine (most at diagnosis)
- Rectal sources (most if >2 cm tumor)
- Most common metastatic sites
- Most common sources of metastases
IV. Classification (WHO, where PI is proliferation index)
- Well-Differentiated endocrine tumor (PI <2%)
- Well-Differentiated endocrine carcinoma (PI 2-15%)
- Poorly differentiated endocrine carcinoma (PI >15%)
V. Presentations of Carcinoid Tumor
- Incidental asymptomatic Carcinoid Tumor (most common)
- Vague non-specific symptoms
- Diagnosis often delayed for up to 1 decade
- Abdominal Pain or Bowel Obstruction may occur
- Carcinoid Syndrome (occurs in 10% of Carcinoid Tumors)
- Late finding for Carcinoid Tumor
- Metastases are usually present when occurs
- Associated with midgut tumors (appendix, ileum)
- See related symptoms below
VI. Symptoms: Carcinoid Syndrome
- Intermittent migratory Flushing of head and neck skin
- Most common symptom
- Rapid color changes between red, white, and violet
- Symptoms accompanying Flushing episodes
- Explosive Diarrhea
- Nausea and Vomiting
- Abdominal Pain or cramping
- Bronchoconstriction
- Symptoms with prolonged Flushing attacks
- Lacrimation
- Periorbital edema
- Provocative
VII. Signs
- Cardiovascular Changes
- Thickening of endocardium (valves, chambers)
- Tricuspid insufficiency
- Pulmonary stenosis
- Right Heart Failure
- Hypotension
- Telangiectasia
- Intestinal hypermotility (borborygmi)
VIII. Differential Diagnosis of Flushing
- Systemic Mastocytosis
- Idiopathic Anaphylaxis
- Alcohol ingestion
- Post-Menopause
- Hyperthyroidism
- Vipoma
- Thyroid Medullary carcinoma
IX. Labs
-
24 hour Urine 5-hydroxyindoleacetic acid (5-HIAA)
- High False Positive and False Negative Rate
- Serum Chromogranin A
X. Imaging: CT Abdomen or MRI Abdomen
- Indicated for abdominal symptoms
- Carcinoid Tumor appearance on imaging
- Mucosal thickening
- Submucosal mass
- Bowel lumen narrowed
- Spiculated mass (if infiltrated)
XI. Imaging: Neuroendocrine tumor localization
- Indium-111 labeled Octreotide Scan (preferred)
- Somatostatin receptor scintigraphy
- Test Sensitivity: 60%
- Test Specificity: 90%
- I-Labeled Meta-iodobenzylguanidine (MIPG)
- Positron Emission Tomography (PET Scan)
XII. Management: Options vary depending on presentation
-
Octreotide 75 to 150 ug up to 750 ug q8 hours
- Indications: Flushing
- Adverse: Hypoglycemia, Steatorrhea, Cholelithiasis
- Alpha-Interferon
- Possibly efficacious as adjunctive therapy
-
Antihistamines
- May be useful in Histamine-related tumors
- Surgery
- Excision of primary tumor
- Tumor debulking
XIII. Complications
XIV. Prognosis
- Five year survival: 67% (variable based on type)
XV. Resources
- Carcinoid Cancer Foundation, Inc
XVI. References
- Abeloff (2000) Clinical Oncology, p. 1379-81
- Dumbro (1999) 5 Minute Clinical Consultant, p. 1192
- Goldman (2000) Cecil Textbook Medicine,p.1295-7
- Kulke (1999) N Engl J Med 340:858-68 [PubMed]
- Robertson (2006) Am Fam Physcian 74:429-34 [PubMed]