Barrett esophagus: diagnostic challenges.

The incidence of esophageal adenocarcinoma and associated mortality has risen dramatically over the past several decades, and, thus, it is increasingly important to understand its pathogenesis and risk factors. Barrett esophagus is the established precursor to esophageal adenocarcinoma that progresses through a metaplasia-dysplasia-carcinoma sequence. Its risk of transforming to carcinoma is not as high as previously reported and there appears to be a biological heterogeneity among patients with this disease. The overall prevalence of Barrett esophagus in the United States ranges from 1% to 25% and is closer to 5% in patients with gastroesophageal reflux disease. Because of the frequency of Barrett esophagus and associated implications, it is important for the practicing pathologist to have a thorough understanding of this disease and its diagnostic pitfalls. In this review, we will discuss issues associated with the diagnosis of Barrett esophagus, including the definition of Barrett esophagus and its distinction from carditis with intestinal metaplasia. We will also discuss challenges in the grading of dysplasia and new variants of dysplasia, including crypt dysplasia and foveolar-type dysplasia. Finally, we will touch upon the evaluation of dysplasia in endoscopic mucosal resection specimens.