Traditional Serrated Adenoma
Definition
- Serrated polyp of the colon and rectum with generalized cytologic dysplasia
Alternate/Historical Names
- Serrated adenoma
- Serrated adenoma type II
Covered separately
Diagnostic Criteria
- Prominent serration of glands
- Usually columnar cells with mucin depleted eosinophilic cytoplasm
- Cytologic low grade dysplasia throughout
- Hyperchromatic elongate nuclei
- Frequent nuclear stratification
- Complex architecture
- Ectopic crypt formation
- Short, crypts oriented at right angles ot main crypt
- Unlike normal crypts they do not reach to muscularis mucosae
- Multiple adjacent crypts contribute to serrated appearance
- In SSA and HP, serrations are predominantly formed by apical cytoplasm
- Filiform variant with long thin surface projections
- Complex villi with serrated surface
- Frequent stromal edema producing bulbous ends
- Lined by tall non-mucinous eosinophilic cytoplasm
- Appears to be restricted to the left colon and rectum
- Usually, but not always, pedunculated and left sided
- May be associated with left sided carcinomas
- Development of focal high grade dysplasia may represent an accelerated phase of carcinoma development
- No clear association with sporadic MSI high carcinomas
- Not typically a component of serrated adenomatous polyposis (hyperplastic polyposis)
- It is now apparent that most, if not all, the polyps of that entity are sessile serrated adenomas
Robert V Rouse MD
Amirkaveh Mojtahed MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting/last update: 1/31/10, 10/10/14
