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Adenomatous Polyps of the Stomach

Definition

  • Circumscribed benign epithelial neoplasm of the stomach

Note:  Flat circumscribed dysplasia is best considered as a flat adenoma, which appears (at least largely) to be of intestinal type, and is included here

Diagnostic Criteria

  • Three distinct types of gastric adenomas have been described and a fourth (oxyntic) proposed
    • Notes:
      • Much of the literature lumps all adenomas together and is thus dominated by the intestinal type, which constitutes more than half of gastric adenomas
      • All may be tubular or villous or mixed
      • Flat and depressed adenomas have been described in limited numbers
        • Appear to be largely, if not all, intestinal type (see below)
          • Goblet cells, Paneth cells and surface orientation in most cases described or illustrated
          • High incidence of carcinoma
    • Intestinal type – most common
      • Contains focal goblet cells or Paneth cells
      • Elongate hyperchromatic nuclei
      • Dysplastic features predominantly involved and accentuated towards the surface
      • Associated with background of atrophic gastritis and intestinal metaplasia
      • No association with familial adenomatous polyposis (FAP)
      • High incidence of carcinoma
        • 45% have high grade dysplasia
        • 25% have invasive carcinoma
    • Foveolar type
      • Lined exclusively by gastric type foveolar cells with apical mucin caps
        • PAS/d +, Alcian Blue –
          • No goblet cells or Paneth cells
      • Elongate hyperchromatic nuclei
      • Frequently associated with familial adenomatous polyposis (FAP)
        • Usually 2 or 3 adenomas
        • (Most of the gastric polyps in FAP are fundic gland polyps)
      • Have been reported in FAP (Wood 2014)
        • No association with background of chronic gastritis or intestinal metaplasia
      • High grade dysplasia and carcinoma rarely if ever present
    • Pyloric gland type
      • Closely packed pyloric gland tubules with frequent cystically dilated tubules interspersed
        • Spread throughout the polyp, not surface oriented like other adenomas
        • PAS/d and Alcian Blue negative
      • No apical mucin cap or goblet cells
        • Frequently has ground glass cytoplasm
        • Usually short columnar cells
      • Nuclei generally small and round
        • About 1/3 show no dysplastic cytologic features
          • Round basal nuclei
        • About 10% show mild dysplastic features
          • Slight elongation and hyperchromasia of nuclei
          • Slight nuclear pseudostratification
        • About 40% show high grade dysplasia
          • Large round nuclei with enlarged nucleoli
          • Loss of polarity
          • Glands may be complex and cribriform
        • About 10% have intramucosal or invasive carcinoma
      • Associated with background atrophic gastritis and intestinal metaplasia
      • Have been reported in FAP (Wood 2014) and Lynch syndrome (Lee 2014)
      • 64% located in fundus
        • Remainder of gastric lesions scattered evenly in other regions
        • 15% in extra-gastric sites usually in patches of gastric heterotopic epithelium
          • Duodenum, bile duct, gall bladder
    • Oxyntic gland polyp/adenoma (proposed entity, Singhi 2012)
      • Clustered glands and cords of oxyntic mucosa
        • Lined by mucus neck, chief and parietal cells
        • Wisps of smooth muscle between clusters
      • Centered in deep mucosa
      • Located in fundus or cardia
      • Lacks significant pleomorphism, mitotic activity, necrosis, desmoplastic response and vascular invasion
      • Earlier reports considered this to be "adenocarcinoma with chief cell differentation / fundic gland type" (Ueyama 2010)
        • No recurrences or metastases reported
    • Rare serrated adenomas have been reported
      • Most are cardiac
      • High incidence of carcinoma
      • Not clear how they fit into above classification
Summary (see details above) [an error occurred while processing this directive]

    Robert V Rouse MD
    Department of Pathology
    Stanford University School of Medicine
    Stanford CA 94305-5342

    Original posting/last update: 11/29/09, 3/26/14

Supplemental studies

Immunohistology

Staining patterns of gastric adenomas
  Intestinal Foveolar Pyloric Oxyntic
MUC2 Pos Neg Neg Neg
MUC5AC Neg Pos Pos Neg
MUC6 Neg Neg Pos Pos

Differential Diagnosis

Summary of differences between gastric adenoma types
Adenoma Type Nuclei Cytoplasm Mucin Assoc Carcinoma/HGD
Intestinal Elongated, hyperchromatic Focal GC and PC Goblets positive,MUC2+5-6- Gastritis and IM High
Foveolar Elongated, hyperchromatic Apical mucin cap PAS+, AB+, MUC2-5+6- FAP None
Pyloric Round, may be bland or atypical Ground glass PAS-AB- MUC2-5+ 6+ Gastritis and IM, FAP, Lynch High
Oxyntic Round, bland Varies with cell type MUC2-5-6+ None None
Assoc = associations, HGD = high grade dysplasia, GC = goblet cells, PC = Paneth cells MUC5 = MUC5AC, IM = intestinal metaplasia, PAS = periodic acid Schiff stain with diastase (neutral mucin), AB = Alcian Blue stain (acid mucin), FAP = familial adenomatous polyposis

 

Gastric Adenoma with High Grade Dysplasia vs. Adenocarcinoma
  • Adenocarcinoma is defined by the presence of invasion into lamina propria or deeper

 

Gastric Hyperplastic Polyp Gastric Adenomatous Polyp, Pyloric Type
Edematous, inflamed stroma Stroma not prominent
Irregular, branched pits Clusters of small regular glands with interspersed cystic glands
Cysts lined by mucin positive foveolar epithelium Cysts lined by mucin negative pyloric gland epithelium

 

Gastric Hyperplastic Polyp with Regenerative Epithelial Atypia Gastric Adenomatous Polyp, Intestinal and Foveolar Types
Atypia associated with erosion and acute inflammation Adenomatous features (intestinal type only) should be independent of inflammation
Edematous, inflamed stroma Stroma not prominent
Cystic dilation usually present Cystic dilation is unusual in adenomas
Frequently has regular, single, prominent nucleoli in regenerative areas Irregular chromatin pattern in most cases

 

Brunner Gland Adenoma or Nodule Gastric Adenomatous Polyp, Pyloric Type
MUC5AC negative MUC5AC positive

 

Esophageal Submucosal Gland Duct Adenoma Esophageal or Gastric Adenomatous Polyp, Intestinal Type
Cytologically bland Cytologically dysplastic
Two cell layers One cell layer
Outer layer has myoepithelial phenotype No myoepithelial component

 

Esophageal Submucosal Gland Duct Adenoma Gastric Adenomatous Polyp, Pyloric Type
Mixed tubular and papillary pattern Tubular, no papillary component
Two cell layers One cell layer
Outer layer has myoepithelial phenotype No myoepithelial component
Inner layer has intensely eosinophilic cytoplasm Pale eosinophilic cytoplasm

Bibliography

  • Bosman FT, Carneiro F, Hruban RH, Thiese ND (Eds). WHO Classifiication of Tumors of the Digestive System, IARC, Lyon 2010
  • Park YD, Lauwers GY. Gastric polyps: classification and management. Arch Pathol Lab Med. 2008 Apr;132(4):633-40.
  • Oberhuber G, Stolte M. Gastric polyps: an update of their pathology and biological significance. Virchows Arch. 2000 Dec;437(6):581-90.
  • Abraham SC, Montgomery EA, Singh VK, Yardley JH, Wu TT. Gastric adenomas: intestinal-type and gastric-type adenomas differ in the risk of adenocarcinoma and presence of background mucosal pathology. Am J Surg Pathol. 2002 Oct;26(10):1276-85.
  • Stolte M, Sticht T, Eidt S, Ebert D, Finkenzeller G. Frequency, location, and age and sex distribution of various types of gastric polyp. Endoscopy. 1994 Oct;26(8):659-65.
  • Chen ZM, Scudiere JR, Abraham SC, Montgomery E. Pyloric Gland Adenoma: An Entity Distinct From Gastric Foveolar Type Adenoma. Am J Surg Pathol. 2008 Sep 30(2):186-193.
  • Vieth M, Kushima R, Borchard F, Stolte M. Pyloric gland adenoma: a clinico-pathological analysis of 90 cases. Virchows Arch. 2003 Apr;442(4):317-21.
  • M'sakni I, Rommani SR, Ben Kahla S, Najjar T, Ben Jilani S, Zermani R. Another case of serrated adenoma of the stomach. J Clin Pathol. 2007 May;60(5):580-1.
  • Ueyama H, Yao T, Nakashima Y, Hirakawa K, Oshiro Y, Hirahashi M, Iwashita A, Watanabe S. Gastric adenocarcinoma of fundic gland type (chief cell predominant type): proposal for a new entity of gastric adenocarcinoma. Am J Surg Pathol. 2010 May;34(5):609-19
  • Singhi AD, Lazenby AJ, Montgomery EA. Gastric adenocarcinoma with chief cell differentiation: a proposal for reclassification as oxyntic gland polyp/adenoma. Am J Surg Pathol. 2012 Jul;36(7):1030-5.
  • Wood LD, Salaria SN, Cruise MW, Giardiello FM, Montgomery EA. Upper GI Tract Lesions in Familial Adenomatous Polyposis (FAP): Enrichment of Pyloric Gland Adenomas and Other Gastric and Duodenal Neoplasms. Am J Surg Pathol. 2014 Mar;38(3):389-93. PubMed PMID: 24525509.
  • Lee SE, Kang SY, Cho J, Lee B, Chang DK, Woo H, Kim JW, Park HY, Do IG, Kim YE, Kushima R, Lauwers GY, Park CK, Kim KM. Pyloric Gland Adenoma in Lynch Syndrome. Am J Surg Pathol. 2014 Feb 10. [Epub ahead of print] PubMed PMID: 24518125.

 

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