Morphometric definition and grading of gastric intestinal metaplasia

Application of endoscopic molecular imaging in diagnosis of gastric intestinal metaplasia

Gastric intestinal metaplasia (GIM) is a precancerous lesion of intestinal type gastric carcinoma. Early diagnosis and follow-up can improve the detection rate of early gastric cancer. In recent years, with the integration of molecular imaging into endoscopy, auto fluorescence endoscopy, Raman spectroscopy, two-photon fluorescence endomicroscopy, and confocal laser endomicroscopy have emerged, which improves the detection rate of GIM. This paper reviews the progress of the application of endoscopic molecular imaging in the diagnosis of GIM.

Immunohistochemical evaluation of keratin 20 expression in intestinal metaplasia types I to III

AIMS

To investigate differences in expression of keratin 20, a cytoskeletal protein in gastrointestinal epithelial cells, in completely differentiated intestinal metaplasia (type I) and incomplete metaplasia (types II and III).

METHODS

Gastric biopsy specimens from 66 patients with intestinal metaplasia were analysed immunohistochemically. Expression of keratin 20 was quantified as the percentage of immunoreactive cells on the tips, the upper, and deep foveolae.

RESULTS

In all specimens keratin 20 was found on the tips and in the upper foveolae of intestinal metaplasia. Keratin 20 was not observed in the deep foveolae. No differences were seen between the antrum and the body. Expression patterns were comparable between types I and III. In type II, however, lower immunoreactivity was found. Both the differences between types I and II as well as between types II and III were significant (p < 0.05).

CONCLUSIONS

Keratin 20 is expressed in metaplastic mucosa as a result of intestinal differentiation. Positive staining found exclusively in juxtaluminal cells occurs only in mature cells containing keratin 20. Lowered immunoreactivity in type II compared with types I and III indicates the different nature of type II intestinal metaplasia. Further studies are needed to shed light on the basic fundamental mechanism responsible for this.

Gastric intestinal metaplasia type III cases are classified as low-grade dysplasia on the basis of morphometry

The aim of this study was to try to place gastric intestinal metaplasia, type III (type III IM) in the stepwise chain of events from atrophic gastritis to cancer. A number of dysplastic, periulcer regenerative, and type III IM lesions were qualitatively diagnosed (and graded) blindly and independently by several pathologists. These lesions were further analysed by means of quantitative parameters, with the aim of differentiating dysplastic from regenerative changes. Inconsistencies between the qualitative and quantitative classification (about 7 per cent of cases) were eliminated and homogeneous groups (low-grade dysplasia, high-grade dysplasia, regenerative changes) were obtained. These cases were taken as the gold standard against which type III IM was compared. The results indicate that the great majority (91.4 per cent) of cases of type III IM fulfil the nuclear and architectural criteria for low-grade dysplasia.

Morphometry of gastric carcinoma: its association with patient survival, tumour stage, and DNA ploidy

Morphometric image analysis of nuclear features was performed on tissue from 46 patients who had had curative resections for gastric cancer. Clinical, pathological, flow cytometric, and follow-up data were available for these patients, which were drawn from a larger, previously reported series. The morphometric data were compared with patient survival, clinico-pathological status, and DNA ploidy. Univariate survival analysis revealed that morphometric parameters were not significantly related to survival, but examination of clinico-pathological data showed lymph node involvement, involvement of the resection margin, and lymphatic invasion to be significantly associated (P < 0.01) with patient prognosis. Multivariate survival analysis using the Cox model found only lymph node and resection margin involvement to be independently related to survival. Comparison of morphometric results with the clinico-pathological parameters showed various features, relating to nuclear size, and its variation to be significantly associated (P < 0.01) with the presence of lymphatic invasion, resection margin involvement, and tumour pattern (intestinal/diffuse). A comparison of morphometry with flow cytometric analysis in these cases showed that nuclear size was not significantly related to either DNA aneuploidy or the DNA proliferative index.