Histopathologic characteristics of early adenocarcinoma in Barrett's esophagus.

To elucidate the early events of cancer development in the columnar cell-lined lower esophagus, 13 esophagectomy specimens with early adenocarcinoma (T1) were histopathologically studied and the morphometry of the lesion was performed on a histologic map. Eleven (84.6%) of the 13 early Barrett's carcinomas were contiguous to both the distinctive specialized-type Barrett's mucosa and squamous epithelium. Furthermore, ten (76.9%) of the 13 tumors had residual squamous islands on the surface. These data suggest that carcinomas in Barrett's esophagus mostly develop at a place very close to the squamocolumnar epithelial border. The distance from the tumor center to the nearest squamous epithelium, including squamous islands, was 2 cm or less in all cases but one. Therefore, the authors conclude that the primary site of cancer development in Barrett's esophagus is the metaplastic columnar-lined area, particularly of specialized type, within 2 cm from the squamocolumnar epithelial border.