Adenomatous Polyps of the Stomach
Differential Diagnosis
- Various types of gastric adenoma
- Adenocarcinoma
- Gastric hyperplastic polyp
- Gastric hyperplastic polyp with reactive atypia
- Brunner gland adenoma
- Esophageal submucosal gland duct adenoma vs intestinal type adenoma
- Esophageal submucosal gland duct adenoma vs pyloric type adenoma
| 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 |
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 |
