Gastric Polyps

DEFINITION
Gastric polyp - hyperplasia, or benign tumours.
Gastric cancer must be ruled out when they are discovered.
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EPIDEMIOLOGY

Age
Predominantly elderly
- common in advanced age; 5% over 80
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AETIOLOGY

Classification is key.

1. hyperplastic (80%)
2. fundic gland polyps
2. adenomatous / neoplastic polyps

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BIOLOGICAL BEHAVIOUR


1. Hyperplastic Polyps
Hyperplastic polyps are an overgrowth of the normal epithelium glandular elements, and are not tumors.
- typically associated with inflammation / adjacent chronic gastritis
Usually in older; antrum > body, often multiple, usually <1cm
Low rate of malignant transformation (<0.5%; and not if <2cm)
But signal higher risk of coexistant cancer due to association with chronic inflammation; 5-10%.

2. Fundic Gland Polyps
Quite common; 3% of endoscopies.
Typically multiple sessile lesions in body.
Sporadic (more common) or can be part of FAP.
Increased proliferation but essentially hamartomatous; no evidence for malignant potential

3. Neoplastic Polyps
Adenomas; tubular.  Can be 'flat'.
Predominantly in antrum; quite uncommon, perhaps 0.2% endoscopies.
Associated with atrophic gastritis and intestinal metaplasia
Show dysplastic features, dysregulation of maturation.
Malignant risk is ~40% in those >2cm.
Co-existant cancer risk significant 5-25%.

Other
Gastroduodenal polyps
Stomach and duodenum
Typically fundic gland or hyperplastic types, associated with FAP.
Risk is that these are adenomas, which is not uncommon, and can be multiple with frequent malignant transformation; typically in duodenum or peri-ampullary.
Natural history
About 30% of adenomatous polyps contain a focus of adenocarcinoma
And 20% of patients with adenomatous polyps have another site of adenocarcinoma.
10% of polyps may undergo malignant change long-term.

Complications
May chronically bleed causing iron deficiency.
Associated with achlorhydria (90%), Vit B12 absorption deficiency (25%).
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MANIFESTATIONS

Symptoms

May be a cause of chronic anaemia.

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INVESTIGATIONS

Endoscopy

Biopsy / remove as appropriate per classification / risk
Perform biopsy, brush biopsy (exfoliative cytologic examination)
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MANAGEMENT

Endoscopy
Excise with snare diathermy

Operative
Remove when >1cm in diameter, or when cancer suspected.
Endoscopic removal first pathway; operative if unable or too large or too many.

Single polyps

Gastrotomy and frozen section.
If adenocarcinoma, will need gastric resection.

Multiple polyps

May require resection; e.g. distal gastrectomy for multiple polyps in antrum.
If scattered throughout stomach, may need antrectomy, then fundal polyps excised.
If symptomatic and scattered may even need total gastrectomy.

Follow-Up
Indicated due to risks of pernicious anaemia and gastric cancer.
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REFERENCES
Companion 4th
Doherty