Histopathological diagnosis of adenocarcinoma in Barrett's esophagus

The present review describes the histological markers of Barrett's esophagus (BE) that make it possible to distinguish between Barrett's carcinoma (BC) and gastric carcinoma. With regard to high‐grade dysplasia, the indications for endoscopic resection (ER) or major surgery for management of BC cannot be decided on the basis of biopsy histology, and the choice between them should be made according to BC invasion depth. Therefore, we recommend that the term ‘well‐differentiated tubular adenocarcinoma’ be used rather than ‘high‐grade dysplasia’ (intraepithelial neoplasia). High‐grade dysplasia is regarded as BC in Japan and other countries such as Germany. Such lesions should not be treated by endoscopic ablation but by ER, because components of invasive carcinoma are frequently present in the mucosa and submucosa, and knowledge obtained from ER samples is needed for additional therapy. Further studies on the relationship between the incidence of nodal metastasis and mucosal depth in mucosal BC are needed to decide the indications for ER. Suchstudies should involve subserial microscopic examination of slices 2–3 mm thick. To resolve the issue of regression of high‐grade dysplasia, international experts in gastroenterological pathology need to conduct histopathological reviews of the first and last samples taken from such cases, as there are large differences between North American, European, and Japanese pathologists in the criteria used for histological diagnosis of dysplasia and adenocarcinoma without clear invasion, and both interobserver and intraobserver variations have been reported. Future studies will need to focus on which carcinomas are curable by ER.