Adenocarcinoma and dysplasias are recognized complications of Barrett mucosa. In the past, the treatment for this carcinoma was esophagectomy. However, new techniques, including endoscopic mucosal resection, sometimes replace esophagectomy and are becoming standard procedures in clinical practice, not just in major medical centers. Pathologists must learn to handle these specimens, which have extensive artifacts. Also, Barrett mucosa has duplicated stromal layers beneath the mucosa that include a new lamina propria and a new muscularis mucosae. We must be aware of these peculiarities because of staging implications. Regardless of new technology, the diagnostic approach to dysplasia depends on the light microscopic interpretation, which is not as reliable or consistent as one would wish. Hopefully, better diagnostic criteria will arise, and perhaps a new histologic stain or a molecular or genetic test will emerge that complements "our eyeballs."