Barrett's esophagus. Practical issues for daily routine diagnosis

Handling and Pathology Reporting of Gastrointestinal Endoscopic Mucosal Resection

Endoscopic mucosal resection (EMR) is a non-invasive alternative to surgery that is now frequently used for resection of early lesions in both upper and lower parts of the gastrointestinal (GI) tract. One of the main advantages of these techniques is providing tissue for histopathological examination. Pathological examination of endoscopically resected specimens of GI tract is a crucial component of these procedures and is useful for prediction of both the risk of metastasis and lymph node involvement.

As the first step, it is very important for the pathologist to handle the EMR gross specimen in the correct way: it should be oriented, and then the margins should be labeled and inked accurately before fixation.

In the second step, the EMR pathological report should include all the detailed information about the diagnosis, grading, depth of invasion (mucosa only or submucosal involvement), status of the margins, and the presence or absence of lymphovascular invasion.

The current literature (PubMed and Google Scholar) was searched for the words "endoscopic mucosal resection" to find all relevant publications about this technique with emphasis on the pathologist responsibilities.

Negative surveillance endoscopy occurs frequently in patients with short-segment non-dysplastic Barrett's esophagus

Surveillance endoscopy of non-dysplastic Barrett's esophagus (NDBE) that fails to detect intestinal metaplasia (IM), or negative surveillance, is known to occur in clinical practice, although the frequency and possible outcomes in a large cohort in clinical practice is not well described. The goals of this study were to define frequency in which negative surveillance occurs and endoscopic outcomes in a screening cohort of short segment NDBE. A retrospective cohort (n = 184) of patients newly diagnosed with short segment NDBE at an outpatient academic tertiary care center between 2003 and 2011 were reviewed. Only those with one or more surveillance endoscopies were included to define a frequency of negative surveillance. Included patients were further assessed if they had two or more surveillance endoscopies and were classified into groups as sampling error or negative IM on consecutive surveillances based on the results of their surveillance endoscopies. The frequency of a negative surveillance endoscopy in all short-segment NDBE patients was 19.66% (92 endoscopic exams were negative for IM of 468 total surveillance exams). A negative surveillance endoscopy occurred in 40.76% (n = 75) patients. Sampling error occurred in 44.12% and negative IM on consecutive surveillance endoscopies in 55.88% of those with ≥ 2 surveillance endoscopies and an initially negative surveillance exam. The frequency of negative IM on consecutive surveillances was 19.00% of all patients who had two surveillance endoscopies. When the index diagnostic Barrett's esophagus segment length was < 1 cm, 32.14% (18/56) of all patients (with ≥ 2 surveillance endoscopies) had negative IM on consecutive surveillance endoscopies. Negative surveillance occurs frequently in short-segment NDBE. When an initial negative surveillance endoscopy occurs, it may be due to either a sampling error or lack of detectable IM on surveillance exam. When a <1 cm segment of NDBE is diagnosed, a significant proportion of patients may go on to have continuously undetected IM on consecutive surveillance endoscopic exams without intervention.

Molecular mechanisms responsible for pathogenesis of Barrett's esophagus

Barrett's esophagus (BE) is defined as the metaplastic conversion of the distal esophageal squamous epithelium to intestinalized columnar epithelium. It is a premalignant condition associated with esophageal adenocarcinoma (EAC) and is the major risk factor for EAC. Recent studies suggest that the molecular mechanisms responsible for the pathogenesis of BE are closely related to transcription factors, signaling proteins and microRNAs (miRNAs). MiRNAs are expected to be used as novel biomarkers for the diagnosis, prognosis assessment and targeted treatment of EAC. This article summarizes recent results involving stem cells, immune factors, transcription factors, DNA methylation, nitric oxide, signaling pathways, microRNAs in the development of BE. Understanding of the molecular mechanisms behind the pathogenesis of BE has important implications for improved management of BE and EAC.

Reduction of E-cadherin by human defensin-5 in esophageal squamous cells

Barrett's esophagus (BE) is metaplastic columnar epithelium converted from normal squamous epithelia in the distal esophagus that is thought to be a precancerous lesion of esophageal adenocarcinoma. BE is attributed to gastroesophageal reflux disease (GERD), and therefore gastric acid or bile acids are thought to be factors that cause epithelial cell damage and inflammation in the gastro-esophageal junction. The decrease of adherent junction molecules, E-cadherin has been reported to be associated with the progression of the Barrett's carcinoma, but the initiation of BE is not sufficiently understood. BE is characterized by the presence of goblet cells and occasionally Paneth cells are observed at the base of the crypts. The Paneth cells possess dense granules, in which human antimicrobial peptide human defensin-5 (HD-5) are stored and secreted out of the cells. This study determined the roles of HD-5 produced from metaplastic Paneth cells against adjacent to squamous cells in the gastro-esophageal junction. A human squamous cell line Het-1A, was incubated with the synthetic HD-5 peptide as a model of squamous cell in the gastro-esophageal junctions, and alterations of E-cadherin were investigated. Immunocytochemistry, flowcytometry, and Western blotting showed that the expression of E-cadherin protein was decreased. And a partial recovery from the decrease was observed by treatment with a CD10/neprilysin inhibitor (thiorphan). In conclusion, E-cadherin expression in squamous cells was reduced by HD-5 using in vitro experiments. In gastro-esophageal junction, HD-5 produced from metaplastic Paneth cells may therefore accelerate the initiation of BE.

Advanced precancerous lesions in the lower oesophageal mucosa: high-grade dysplasia and intramucosal carcinoma in Barrett's oesophagus

Adenocarcinoma developed in Barrett's oesophagus is a tumour with an increasing incidence and still a poor prognosis. The only marker that can be used for surveillance remains dysplasia (intraepithelial neoplasia), especially when it is high-grade, that precedes intramucosal carcinoma. New forms of dysplasia have been described in complement to the classical intestinal type (foveolar dysplasia, basal crypt dysplasia). High-grade dysplasia and intramucosal carcinoma are diagnosed on biopsies taken during endoscopy. Standard endoscopy is now challenged by various techniques that represent recent major technical improvements (chromoendoscopy, virtual chromoendoscopy, optical frequency domain imaging, confocal laser endomicroscopy). In numerous cases, high-grade dysplasia and intramucosal carcinoma can be treated by endoscopic procedures, allowing a precise histopathological diagnosis on the resected specimen (endoscopic mucosal resection, submucosal endoscopic dissection) or destroying the neoplastic tissue. Radiofrequency ablation is currently considered as the best available technique for treatment of flat high grade dysplasia and for eradication of residual Barrett's mucosa after focal endoscopic mucosal resection.

[Subjective grading of Barrett's neoplasia by pathologists: correlation with objective histomorphometric variables]

Even though pathologists are trained to recognize the same histological features for the diagnosis and grading of different histological images, not all pathologists are influenced to a similar level of intensity by the same morphological characteristics of the tissue when scoring Barrett's dysplasia/neoplasia. The variables which most pathologists have intuitively chosen to use for scoring of the severity of Barrett's changes are mainly those related to the general tissue architecture, such as nuclear crowding, orientation and stratification. Interestingly, nuclear size is not used by most pathologists but nuclear pleomorphism and symmetry does influence a significant number of pathologists. Maybe the most difficult variables for the human eye to recognize are variables of chromatin texture (such as margination or heterogeneity), the predictive importance of which has been demonstrated in a previously published work. Textural variables may therefore remain the subject of a computerized analysis. Nevertheless, the fact that a few pathologists do actually correlate with nuclear texture in scoring, argues in favor of making further attempts to train pathologists to also rely on texture, similar to cytologists, when scoring Barrett's dysplasia.