Esophageal squamous dysplasia

Esophageal squamous dysplasia (ESD) appears to be the most important precursor for squamous cell carcinoma (SCC), and this observation is supported by early molecular findings. Pathologists in high incidence areas of the world, such as China, frequently may encounter ESD during surveillance cytology and biopsy screenings of high risk populations. ESD in low risk areas, such as the United States, is more commonly seen in esophagi resected for squamous cell carcinoma. As at other sites, ESD can be graded histologically depending on the thickness of epithelial involvement and cytologically based largely on nuclear size and chromatin features. Most ESD lesions are endoscopically visible, especially if the esophageal mucosa is sprayed with iodine, allowing for directed biopsy. Several studies have shown that important differences in histologic and cytologic diagnosis and grading exist between Western pathologists and those in China or Japan. Despite these findings, the risk of developing invasive SCC is closely correlated to the severity of ESD encountered. Correct recognition of ESD thus is important.