The clinical significance of gastric epithelial dysplasia

Pathology and Clinical Relevance of Gastric Epithelial Dysplasia

Gastric dysplasia is defined as an unequivocally neoplastic epithelium. Dysplastic lesions are characterized by cellular atypia reflective of abnormal differentiation and disorganized glandular architecture. The last few years have been marked by a refinement of the prognosis and risk of progression of gastric dysplasia and the recognition of novel morphologic patterns of dysplasia. Determination of the correct diagnosis and grade of dysplasia are critical steps since it will be predicting the risk of malignant transformation and help tailor appropriate surveillance strategy. This review describes the morphologic characteristics of conventional dysplasia and nonconventional gastric dysplasia that have been more recently characterized.

Dysplasia in Gastric Mucosa and its Reporting Problems

BACKGROUND

The recognition, terminology used and histopathologic evaluation of two essential elements in gastric carcinogenesis, atrophy and dysplasia, are characterized by controversy.

MATERIALS AND METHODS

One hundred fifteen cases, with slides and their histopathologic reports from the archive of the Laboratory of Pathology were studied for the diagnostic value, reporting of dysplasia, interobserver variability, the relation of dysplastic lesions with inflammation, atrophy and metaplasia. After retrospectively studying the histopathologic reports from the archive we distributed the cases according to endoscopic and histopathologic diagnosis, together with the reexamination of the slides. The comparison of the median values of the numeric variables was made with the Mann-Whitney test (non-parametric equivalent of the Student's "t" test).

RESULTS

The endoscopic clinical diagnosis were: malignancy/suspicious for malignancy 88 cases (76%) and non-neoplastic diagnosis (like ulcer or gastritis) 27 cases (24%). From the reexamination of the cases it resulted that there is no difference in reporting the malignancy, but there is a difference in the cases reported as dysplasia (p = 0.001) and negative for neoplasia (p = 0.063, borderline).

CONCLUSION

Clinicians and pathologists can feel directly the discrepancy called "interobserver variability" and should be assured that the use of guidelines will cause a lowering of this variability.

The association between gastric endoscopic findings and histologic premalignant lesions in the Iranian rural population

Atrophic gastritis, intestinal metaplasia, and gastric dysplasia are histologic premalignant lesions (PMLs). Correlation between the gastric endoscopic findings and histologic PMLs is not clear. This study was designed to determine the possible association of endoscopic findings and histologic PMLs.Over 28 months gastric endoscopic findings of consecutive rural patients with dyspepsia were categorized into 3 groups: 1-normal, 2-ulcerative with or without concurrent abnormality, 3-abnormal non-ulcerative. Biopsies of antrum and body were taken from all included patients and examined for the presence of histologic PMLs. Any mucosal abnormality was also biopsied.From 7340 evaluated patients, an overall of 1973 patients were included. 55.7% of patients were in group 1; 3.8% in group 2 and 40.5% in group 3. A within sex analysis showed that the majority of male patients were in PMLs subgroup (P < 0.001) likewise in groups 2 and 3 (P < 0.001). The prevalence of histologic PMLs in groups 2 and 3 was significantly higher than group 1 (P < 0:001) but the difference was not significant between groups 2 and 3 (P = 0.484). Mean (±SD) age of patient with PMLs was 50.25 ± 17.71 whereas in patients without PMLs was 41.16 ± 16.48 (P < 0.001).This study has showed that abnormal gastric endoscopic findings, male sex and increased age can be considered as risk factors of the formation of histologic PMLs. Until further investigations we propose that any abnormality on gastric mucosa (ulcerative or non-ulcerative) could be biopsied for the evaluation of probable histologic PMLs especially in old men.

Gastric epithelial dysplasia: the Western perspective

The need for early diagnosis of gastric cancer is emphasized by the fact that gastric cancer remains the second most common cause of cancer related deaths worldwide. The aggressive surveillance and definite therapy for low and high-grade dysplasia, which can be achieved endoscopic means, remains the cornerstone of clinical management. Although the precursor status of dysplasia is not contested, its classification is controversial and fraught with marked inter-observer variations. Most cases of gastric dysplasia have an "intestinal" phenotype referred to as adenomatous dysplasia. Hyperplastic (type II dysplasia) is another less common variant. The progression of dysplasia to carcinoma is paralleled by a stepwise accumulation of multiple, but yet uncertain, genetic abnormalities. There are no immunohistochemical or molecular assays that can stratify with certainty the risk of progression to cancer. Given the low rate of transformation of low-grade dysplasia, annual endoscopic surveillance with re-biopsy is advocated. A diagnosis of indefinite for dysplasia should also prompt endoscopic surveillance. A diagnosis of high-grade dysplasia is more ominous, since it progress to cancer in most cases. However, the novel imaging and endoscopic modalities have modified management strategies with mucosal lesions amenable to endoscopic resection, while surgical resection is reserved to invasive adenocarcinoma with submucosal invasion.

Gastric preneoplastic lesions and epithelial dysplasia

The incidence of gastric cancer is declining; however, it remains the second most common cause of cancer-related deaths worldwide. This article describes gastric preneoplastic lesions and epithelial dysplasia. The possible role of Helicobacter pylori infection is emphasized.

Gastric epithelial dysplasia and adenoma: historical review and histological criteria for grading

Gastric epithelial dysplasia (GED) hypothetically is a straight-forward concept: dysplastic epithelium replacing the normal gastric epithelium of the stomach. However, since its inception several decades ago, the term GED has become progressively complex and confusing because of differences in definitions and nomenclature that have been based on cytological, microscopic, endoscopic, or gross features. This has resulted in the terms "dysplasia," "adenoma," "flat adenoma," and "depressed adenoma." Some authors have also included reactive changes under the term "dysplasia."

Gastric epithelial dysplasia in the natural history of gastric cancer: a multicenter prospective follow-up study. Interdisciplinary Group on Gastric Epithelial Dysplasia

BACKGROUND/AIMS

Because the precancerous significance of gastric epithelial dysplasia (GED) is still under debate, this study attempts to ascertain whether a prospective follow-up of GED can contribute to clarifying its clinical and pathological relationships with gastric cancer (GC).

METHODS

One hundred twelve patients with mild (G1), moderate (G2), and severe (G3) GED or diagnosed as indefinite for dysplasia were prospectively followed up with a standardized endoscopic and bioptic protocol.

RESULTS

Evaluation of GED outcome refers only to 93 patients with a follow-up period longer than 12 months. Regression of dysplasia was documented in 36%, 27%, and 0% of G1, G2, and G3 GED cases, respectively. Progression to more severe dysplasia or evolution into GC was detected in 21%, 33%, and 57% of G1, G2, and G3 GED cases, respectively. Evolution into GC was documented for all grades of dysplasia and correlated significantly with high-grade atrophic gastritis. A high prevalence of early GC (86.9%) was also observed.

CONCLUSIONS

GED is a pre-invasive lesion, and carcinomatous evolution increases proportionally with its histological grade. Bioptical follow-up is mandatory for all histological grades of GED and significantly increases the likelihood of GC being detected in its early stages.

Photodynamic therapy of the normal rat stomach: a comparative study between di-sulphonated aluminium phthalocyanine and 5-aminolaevulinic acid

Dysplasia in the upper gastrointestinal tract carries a risk of invasive malignant change. Surgical excision of the affected organ is the only treatment available. Photodynamic therapy has been shown to be promising in the treatment of early and superficial tumours and may be useful for the ablation of dysplastic mucosa. Because of the diffuse nature of the disease, such treatment would necessarily involve destruction of large areas of mucosa and it is desirable to confine its effect to the mucosa in order that safe healing can take place. By means of photometric fluorescence microscopy, we have studied the pattern of photosensitisation in the normal rat stomach using di-sulphonated aluminium phthalocyanine (AlS2Pc) and 5-aminolaevulinic acid (ALA) as photosensitisizers. AlS2Pc resulted in a panmural photosensitisation of the gastric wall with the highest level encountered in the submucosa. The mucosa and muscularis propria were sensitised to equal extent. Following light exposure, a full thickness damage resulted. ALA is a natural porphyrin precursor and exogenous administration gave rise to accumulation of protoporphyrin IX (PPIX) in the cells. The resultant pattern of photosensitisation was predominantly mucosal and its photodynamic effect was essentially confined to the mucosa. ALA produced a selective photosensitisation of the gastric mucosa for its photodynamic ablation with sparing the underlying tissue layers.

Gastric epithelial dysplasia: a prospective multicenter follow-up study from the Interdisciplinary Group on Gastric Epithelial Dysplasia

To assess the evolution of gastric epithelial dysplasia (GED), a prospective multicenter study was based on a protocol of repeated endoscopies and biopsies. To date, 134 cases (0.4% of all patients endoscopically examined in the same period) have been diagnosed as having GED and 80 of those have had an "adequate" follow-up (at least three endoscopies). Mean follow-up time was 18 months. Gastric epithelial dysplasia was mild in 59% of cases, moderate in 25%, and severe in 10%. Six percent of the patients had lesions that were "indefinite for dysplasia." Chronic atrophic gastritis (40%), gastric ulcer (32%), gastrectomy (10%), and polyps (9%) were the most frequently associated lesions. The term "regression" was adopted for GED no longer detectable during follow-up and the term "progression" was used when more severe changes or cancer was detected. Mild GED regressed in 66% of cases, persisted in 15%, and progressed in 19% (three cases to moderate, one to severe, and five to cancer). Moderate GED regressed in 30% of patients, persisted in 30%, and progressed in 40% (one to severe GED and seven to cancer). Severe GED regressed in 12.5% of patients, persisted in 12.5%, and progressed to cancer in 75%. Of the five patients with lesions indefinite for dysplasia, two had no dysplastic changes at follow-up and three had cancer diagnosed. Ten of 21 cases of cancer (48%) were at the early stage. The diagnosis was reached within the first year of follow-up in 14 cases and after 1 year in seven (13 to 39 months). Fifteen of 21 cases of cancer were diagnosed in gastric ulcer patients. In conclusion, GED is an infrequent finding and its biologically neoplastic significance is confirmed by the results of the follow-up study: (1) in its mild form, it tends to regress but adequate subsequent check-ups are mandatory as it may associate with or evolve as cancer; (2) patients with moderate GED require strict follow-up since the lesion shows a higher cancer risk; (3) surgery is indicated for severe GED because gastric cancer develops in 75% of cases; and (4) patients with lesions indefinite for dysplasia should immediately undergo repeat endoscopy and biopsy. Such an approach allows gastric cancer to be detected at an early stage in a much higher percentage of cases than may be expected.

High grade dysplasia of the gastric mucosa: a marker for gastric carcinoma

The natural history of gastric epithelial dysplasia and its relation to gastric cancer are ill defined. A consecutive series of 40 patients with an initial diagnosis of gastric epithelial dysplasia based on examination of endoscopic biopsies has been reviewed to determine the clinical outcome and to evaluate a two tier histological grading system as a predictor of the risk of cancer. On review, only 20 of the 40 patients were considered to have true dysplasia: seven patients had low grade dysplasia and 13 had high grade dysplasia. Of the 13 patients with high grade dysplasia, 11 (85%) were found to have gastric cancer within 15 months. Of the 10 patients with high grade dysplasia who underwent gastrectomy, six were found to have early gastric cancer, three had cancer invading into the muscularis propria, and none had lymph node metastases. High grade dysplasia is thus a marker of gastric cancer. Moreover, the cancers associated with high grade dysplasia are usually pathologically favourable and curable. The finding, by an experienced pathologist, of high grade dysplasia in two separate sets of endoscopic biopsies is therefore an indication for radical surgical treatment, provided that the patient's age and general condition permit such an approach.

Gastric dysplasia: inter-observer variation, sulphomucin staining and nucleolar organizer region counting

Gastric dysplasia is regarded as a pre-neoplastic lesion and is generally believed to have higher potential for malignant transformation with increasing grade. To obtain consistency in diagnosis and management, reproducible diagnostic criteria are needed. We have used the classification system of the International Study Group on Gastric Cancer--ISGGC and investigated the interobserver variation in histological diagnosis. A Kappa statistic of 0.579, which reflects moderate agreement, was obtained for variation between two experienced pathologists. The prevalence of type III intestinal metaplasia was studied and found to occur in 55% of dysplastic areas, but in only 9% of hyperplastic areas (P less than 0.01). In addition, the correlation of mean nucleolar organizer region (AgNOR) counts with diagnostic categorization was investigated. A significant inter-observer variation was found between an experienced pathologist and a postgraduate student and only one of the observers obtained statistically significant separation of mean AgNOR counts between the categories of high-grade dysplasia, low-grade dysplasia, atypical hyperplasia, simple hyperplasia and normal.

Gastric dysplasia

The morphological diagnosis of gastric dysplasia is based on the presence of changes in the architecture, cytology and differentiation of the epithelium and mucosal glands. Two morphological types exist: gastric (foveolar) and metaplastic. Definite morphological criteria for gastric dysplasias can be presented. The present morphological grading of dysplasia into mild, moderate or severe is, however, arbitrary and subjective. The available investigations show that dysplasia and overt carcinoma have several biological and epidemiological links that indicate that a dysplasia-cancer sequence operates in the pathogenesis of at least a proportion of gastric carcinomas. The data available in the literature strongly indicate that severe dysplasia is highly predictive for coexisting or shortly appearing carcinoma. The literature on the clinical significance of dysplasia of mild or moderate grade, however, is as yet scanty and inconsistent.