Person:

Srivastava, Amitabh

Gastric epithelial dysplasia (GED) can be morphologically categorized into adenomatous (or intestinal) and foveolar (or gastric) types. Although limited genetic differences have been demonstrated between these subtypes, the expression of various mucins has not been systematically evaluated in this context. Endoscopic mucosal resections from 69 cases of GEDs were evaluated for the expression of MUC2, MUC5AC, MUC6, and CD10. The results were correlated with morphologic categorization and clinicopathologic parameters. GED was classified as adenomatous, foveolar, or hybrid (showing features of both types), on the basis of histologic evaluation. The neighboring intestinal metaplasia (IM) was also evaluated. An adenomatous morphology was seen in 45%, hybrid type in 33.3%, and a “pure” foveolar type was seen in 21.7% of the cases. Foveolar GED was often depressed/flat on endoscopy and showed a statistically significant association with high-grade morphology (P=0.046). Immunohistochemistry confirmed the histologic stratification. The foveolar and hybrid types were more often positive for MUC5AC (P=0.0001 for both) and negative for CD10 (P=0.019 and 0.016, respectively) as compared with adenomatous GED. High-grade morphology was associated with MUC5AC expression regardless of the morphologic phenotype (P=0.026). Foveolar (73.3%) and hybrid (86.9%) GEDs were associated more often with IM showing a retained expression of gastric type mucin than adenomatous GED (29%) (P<0.01 for both). In contrast, adenomatous type (58.1%) of GED was significantly associated with IM showing a complete intestinal phenotype (CD10+) compared with the foveolar (13.3%) and hybrid types (17.4%) of GED (P=0.005 for both comparisons). In conclusion, our study indicates that foveolar and adenomatous types of GED have distinct clinicopathologic features, mucin profiles, and association with different types of IM.

CDX2 is an intestinal transcription factor responsible for regulating the proliferation and differentiation of intestinal epithelial cells. In gastric adenocarcinoma, CDX2 expression is known to be associated with limited invasiveness and intestinal phenotypes. The aims of this study were to analyze CDX2 expression in a series of well-characterized cases of gastric epithelial dysplasia, based on the morphologic and mucin phenotypes, and also to analyze CDX2 expression along the metaplasia–dysplasia–carcinoma sequence. CDX2 expression was evaluated in 69 cases of gastric epithelial dysplasia, 88 cases of intestinal-type early gastric cancers, and 56 cases of advanced gastric cancers. Increased CDX2 expression was more frequently associated with adenomatous-type gastric epithelial dysplasia (27/31, 87%) compared with foveolar (7/15, 47%) or hybrid (10/23, 44%) types of gastric epithelial dysplasia (P=0.001). CDX2 expression correlated with an increase in CD10 expression (P=0.005), and a decrease in MUC5AC expression (P=0.001) in gastric epithelial dysplasia. CDX2 expression was also gradually decreased from gastric epithelial dysplasia, to early and advanced gastric cancers (present in 64, 40 and 27% of the cases, respectively). A negative correlation was also observed between CDX2 expression and the depth of tumor invasion. Our results indicate that CDX2 expression is associated with specific morphological and mucin phenotypes of gastric epithelial dysplasias, and decreases progressively with the advancing stage of gastric cancers, suggesting a possible tumor suppressor role for CDX2.

Sessile serrated adenoma (SSA) is the proposed precursor for microsatellite unstable colorectal carcinomas and some authorities recommend that SSAs should be managed similar to adenomas. The aim of our study was to determine whether serrated polyps can be classified with sufficient consistency to support current treatment recommendations. One hundred eighty-five serrated polyps were classified as hyperplastic polyp (HP), SSA, or traditional serrated adenoma (TSA) by 5 pathologists blinded to clinical data. The observers documented which histologic features they considered most helpful in reaching their diagnosis in each case. In a second round, the observers were provided with polyp site and size. After reaching a consensus on minimum criteria for SSA and TSA, the pathologists classified another set of 50 polyps. The interobserver concordance was calculated using kappa statistics. In the first round, the overall interobserver agreement was moderate (kappa=0.55). Concordance for HP and SSA was moderate whereas it was nearly perfect for TSA. In the second round, there was no improvement in the concordance. All observers relied more often on architectural features than on cytologic ones to distinguish SSA from HP and agreement was reached that architectural features should provide the basis for the diagnosis of SSA. Subsequently, interobserver concordance was slightly improved but remained moderate (kappa=0.58). Interobserver agreement for the diagnosis of serrated polyps is moderate. However, this level of variability is acceptable because the presence of SSA indicates increased risk of developing additional serrated polyps and carcinoma, and surveillance is appropriate.