Gastric polyps

Section: UGI Sub-section: Gastric

Definition, Incidence, Aetiology and Clinical

• Mass that projects above the level of the surrounding mucosa
  • Usually benign epithelial elevations of the gastric lining
• Incidence:
  • Incidence ≈ 1%
  • Most common benign lesion of the stomach
• Aetiology
  • Mostly unknown
  • Fundic-gland polyps
    • ? PPIs
      • May increase risk due to glandular hyperplasia and decreased luminal flow
  • Hyperplastic polyps
    • Due to inflammation / mucosal damage (e.g. H pylori)
• Clinical
  • Usually asymptomatic
  • Usually incidental finding seen at 2-3% of gastroscopies
  • Occasionally bleed
  • Occasionally prolapse through pylorus → Pain & vomiting

Classification

• Epithelial:
  • Fundic Gland Polyps (46%)
  • Hyperplastic polyp - Overgrowth of normal epithelium
  • Adenomatous (6%) → Associated with FAP & adenocarcinoma
  • Heterotopic (e.g. Ectopic pancreatic mucosa)
  • Hamartomatous – e.g. Peutz-Jeghers or Cowden’s syndrome
• Neuroendocrine
  • Carcinoid
• Lymphohistocytic
  • Inflammatory
  • Lymphoid Hyperplasia
• Mesenchymal
  • GIST, Leiomyoma, Lymphoma

Pathology

Fundic Gland Polyps

• Exclusively in fundus & body
• Hyperaemic, sessile, with smooth contour
• 3 main contexts
  • Sporadic
    • No clinical consequence
    • 2-3mm sessile polyps
  • Familial
    • FAP (APC mutation) or sporadic (β-catenin mutation, found in 10% of population)
      • Dysplasia only found in FAP associated fundic gland polyps
  • Chronic PPI use
    • Get chronic acid suppression
    • Up-regulation of Gastrin
    • Parietal Cell Hypertrophy (Glandular Hyperplasia)
    • Cystically dilated glands (non-neoplastic)
• Risk of dysplasia
  • Sporadic lesions (<1 percent),
  • Reported up to 41 percent in fundic gland polyps that arise within the context of an inherited syndrome

Hyperplastic Polyps

• Composed of epithelial and stromal components
• Typically located in the Antrum
  • < 2cm diameter
  • Sessile or pedunculated
• Usually occurs in the setting of Chronic Gastritis (H. pylori)
  • Polyps regress with H. Pylori eradication
• Low risk of dysplasia with mutation in p53
  • Usually only larger polyps > 2cm
  • Risk of malignancy increased if > 1cm or pedunculated
• Surrogate markers for increased cancer risk
  • Synchronous/metachronous gastric cancers found in up to 6% of patients
    • Like LCIS in Breast Cancer
    • Esp. with Chronic Gastritis (H. pylori related)

Harartomas

• Hamartomas, Inflammatory, Heterotropic Polyps
  • Negligible malignant potential
  • Association with familial polyposis syndromes
    • Associated with increased risk of Gastric ca.
  • Peutz-Jeghers syndrome
  • Juvenile polyposis
  • Cowden’s syndrome

Adenomas

• Typically occur in the presence of Chronic Atrophic Gastritis
  • Can be flat or polypoid
  • Usually < 2cm
  • Usually solitary
• Usually antral, sessile, solitary, eroded
• Associated with Adenocarcinoma
  • Malignant potential 10%-20%
• Classification:
  • Intestinal type
    • Patients > 50yrs
    • M > F 3:1
    • Precursors to gastric adenocarcinoma
    • Increased risk with size
    • 50% adenoma > 2cm harbour adenocarcinoma
  • Non-intestinal type
    • Rare

Management

• Excise if
  • Symptomatic

  • 1cm

  • Adenomatous
• If > 2cm, should biopsy polyp to exclude malignancy
  • May need gastrectomy
• Follow-up scope needed post-removal of adenomatous polyps