Review Note

Last Update: 02/18/2024 05:30 AM

Current Deck: Part 2::1. Subsites::Gastrointestinal tract::Carcinoid tumour

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GI | Carcinoid | 1.6.5 | Specific sites | Stomach
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Definition
  • Usually well-differentitated, non-functioning enterchromaffin-like cell carcinomas (ECL).
  • 3 types are recognized:
    • Type I (80%) – associated with autoimmune chronic atrophic gastritis Pathogenesis: ECL cells stimulated yb high gastrin levels associated with chronic atrophic gastritis.
    • Type II (5%) – associated with MEN-1 and Zollinger-Ellison syndrome (caused by a separate gastrin-producing neoplasm, usually in the pancreas or samll intestine) Pathogenesis: Hypergastrinaemia caused by gastrin-producing neoplasm stimulates ECL cells in stomach
    • Type III (15%) – sporadic. Ocucr in absence of atrophic gastritis, Zollinger-Ellison syndrome or MEN1.
  • Also EC, serotonin-producing, G-cell, gastrin producing, small and large cell
 
Epidemiology
  • I: Account for up to 20-40% of all GI carcinoids.
  • A: Mean age of 60 years.
  • S: Females much more common than males : 2.5:1. 
  • G: Higher incidence in Japan  due to high incidence of chronic atrophic gastritis.
  • Small cell is uncommon and is commoner in men.
Aetiology
  • Gastrin: trophic for ECL-cells in humans and experimental animals.
  • Autoimmune chronic atrophic gastritis:
  • Due to antibodies to parietal cells of oxyntic mucosa. Leads to chronic atrophic gastritis and increased gastrin production.
 
Localisation
  • ECL-cell carcinoids are found in mucosa of the body-fundus.
  • Type I and II lesions are usually small and multiple.
  • Type III lesions are generally solitary.
 
Pathology
Macro:
  • Small circumscribed polyps
  • Type II: thickened gastric wall due to hypertrophic-hypersecretory gastrophathy
  • Type III larger and more infiltrative.
Micro
  • ECL:
    • Glandular, trabecular or rarely insular patterns
    • Bland nuclei with salt and pepper chromatin, rare mitotic figures, prominent vessels, no necrosis
    • Type III more aggressive with mitoses and necrosis
  • EC-cell, serotonin producing: vary rare in stomach: rounded nests of closely packed small tumour cells with peripheral palisading.
  • Gastrin-cell: thin trabecular-gyriform or solid nest pattern. Cells are uniform with scanty cytoplasm. Immunoreactive for gastrin.
  • Small cell: small packed cells with hyperchromatic nuclei and nuclear moulding.
  • Large cell neuroendocrine: large cells with organoid, nesting, trabecular, rosette-like and palisading patterns. Cytoplasm is more abundant and nuclei are more vesicular with prominent nucleoli.
IHC:
  •  +ve for chromogranin, keratin, neuron-specific enolase; CK7-, CK20-
EM: 
  • Dense core secretory granules
 
BB
  • Type I
    • Indolent
    • Usually <1cm size
    • LN mets <5%
    • Liver mets 2.5%
  • Type II
    • Indolent
    • LN mets 30%
    • Liver mets 10%
  • Type III
    • Most aggressive
    • 70% have LN and distant mets
    • Median survival 28 months
Management
  • Type I 
    • Endoscopic resection for small tumours (majority) → endoscopic surveilance every 6-12 months
    • Tumours increasing significantly in size / multiple tumours - consider antrectomy
  • Type II
    • Endoscopic resection → surveillance
    • Can use octreotide/lanreotide if symptomatic
  • Type III
    • Radical resection and lymphadenectmoy
    • Consider smaller wedge resection and no lymphadenectomy for smaller tumours with no evidence of nodal disease
Further information, not for memorising (no card)
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