Diffuse Gastric Polyposis

Persistent bloating, epigastric discomfort, and increased gastric acidity prompted a 47-year-old woman to seek medical care. Gastroesophageal reflux disease was diagnosed; antacids and H₂-blockers were prescribed but provided no relief.

Subsequently, an upper GI tract endoscopic examination revealed an erythematous and ulcerating esophagus (A) and multiple sessile polyps predominantly in the fundus of the stomach (B and C). Biopsies were performed; histopathologic examination identified Barrett esophagus and hyperplastic polyps. Helicobacter pylori was also found in the stomach.

Drs Tausif Zar and Khalid Aziz of the University of Connecticut in Farmington write that in patients who have diffuse gastric polyposis, multiple polyps develop over a large area of the gastric mucosa. These lesions can occur sporadically or in polyposis syndromes, such as familial adenomatous polyposis (FAP), Peutz-Jeghers syndrome, juvenile polyposis, Gardner syndrome, and Cowden disease.

Typically, the polyps are incidental findings on upper GI tract films or endoscopies. Gastric polyps are found on 2% to 3% of all gastroscopies; 20% to 33% are multiple lesions.^1-3 Men and women are equally affected. The lesions usually occur in middle-aged or elderly patients; however, children with FAP or juvenile polyposis are also affected.

Most gastric polyps are non-neoplastic.¹ In a 4-year study that included 13,000 adults who underwent endoscopy, the overall incidence of gastric polyps was 1.2%; 75.6% of these were hyperplastic, 6.6% were adenomatous, and the remainder were inflammatory.^2,3 Another study that included 5000 adults determined that 75.3% of the polyps found were hyperplastic and 10% were adenomatous; the rest were carcinoid, Peutz-Jeghers, and juvenile polyps or Brunner gland hyperplasia.

Hyperplastic polyps are also called regenerative polyps because they represent an exuberant regenerative response of the gastric foveolar cells.^2,3 The polyps appear singly or in multiples, primarily in the antrum. The pathogenesis of these lesions is unclear; they may be attributable to mucosal irritation or to chronic inflammation with or without H pylori infection. Over time, the polyps may regress, remain stable, or increase in size.

Most patients with these lesions are asymptomatic; however, some experience vague epigastric discomfort, bloating, anorexia, nausea, vomiting, hematemesis, melena, anemia, or obstruction. Achlorhydria is common.⁴

Although the incidence of malignant transformation in hyperplastic polyps is very low (0.5% to 7.1%), lesions that are larger than 2 cm in diameter and pedunculated have the greatest potential. The risk of malignancy in multiple hyperplastic lesions is as high as 3.6%.¹ These lesions may presage malignancy elsewhere in the stomach, and some reports note a greater incidence of nonmalignant mucosal gastric polyps in persons with colon cancer or colonic polyps or neoplasms.²

Adenomatous gastric polyps have a higher rate of malignant transformation than colonic adenomas.¹

Fundic gland polyps, which comprise about half of all gastric polyps, appear in healthy mucosa and are harmless. They arise sporadically or in association with FAP or Gardner syndrome.³

Management depends on histologic findings.⁵ Patients with H pylori infection require antibacterial therapy. Polyps that are larger than 1 to 2 cm probably warrant removal, because they are more likely to harbor focal carcinoma. Consider a subtotal gastrectomy or wedge resection when dysplasia, multiple adenomatous polyps, or carcinoma is present. Frankly invasive cancer in a hyperplastic polyp is rare. If an excised polyp shows early carcinoma that is moderately or well-differentiated and confined to the mucosa and the patient is otherwise free of polyp carcinomas, surgery is not necessary; regular follow-up is sufficient.

REFERENCES:1. Oberhuber G, Stolte M. Gastric polyps: an update of their pathology and biological significance. Virchows Arch. 2000;437:581-590.
2. Bynum TE. Gastric polyps. Up To Date. 2001;9(2). Available at: www.uptodate.com. Accessed August 8, 2001.
3. Odze RD, Antonioli DA. Pathology and clinical features of gastric polyps. Up To Date. 2001;9(2). Available at: www.uptodate.com. Accessed August 8, 2001.
4. Spiro HM. Multiple polyposis of the stomach. In: Spiro HM. Clinical Gastroenterology. 4th ed. New York: McGraw-Hill; 1993.
5. Lau CF, Hui PK, Mak KL, et al. Gastric polypoid lesions: illustrative cases and literature review. Am J Gastroenterol. 1998;93:2559-2564.