Adenocarcinoma of the Stomach
Supplemental Studies
Immunohistology
- Hepatoid variant
- Albumin positive
- CD10 frequently stains canaliculi
- CDX2 variable
- Adjacent gastric carcinoma positive
- Heppar1 usually negative or weak focal staining
- Alpha fetoprotein variable
- Not specific for hepatoid
- PLUNC positive but very focal
- (Palate, LUng, Nasal epithelium Carcinoma associated protein)
- Associated carcinomas more extensively positive
- Gastric adenocarcinomas NOS 7%
- Hepatocellular carcinoma 0%
- Only one report so far (Sentani) and the staining looks very focal
- Hereditary diffuse gastric carcinoma
- E cadherin and beta catenin negative or reduced in intramucosal carcinoma foci
- Both may be positive in deeply invasive carcinomas
- Ki67 <2% in microscopic carcinoma foci found on prophylactic gastrectomy
| Adenocarcinoma Type |
CDX2 Staining |
| Colorectal |
70-98% |
| Small intestine |
60% |
| Stomach |
60-70% |
| Endocervix |
30% |
| Ovary primary mucinous |
40-70% |
| Uterus |
10-15% |
| Bile duct |
13-25% |
| Lung |
0-12% |
| Pancreas |
0-32% |
| Liver |
0% |
| Breast |
0% |
Genetic studies
- Hepatoid variant
- Hereditary diffuse (poorly cohesive) gastric carcinoma
- Most common abnormality is mutation in E cadherin CDH1 gene (40% of families)
- No other consistent mutations found yet
- Criteria for testing (Fitzgerald 2010)
- Two gastric carcinomas in family, one diffuse and under age 50
- Three diffuse carcinomas in 1st or 2nd degree relatives, any age
- Diffuse carcinoma under age 40
- Personal or family history of diffuse gastric carcinoma and lobular breast carcinoma, either one under age 40
- Consider testing if signet ring carcinoma in situ is detected adjacent to diffuse gastric carcinoma (WHO 2010)
