Adenocarcinoma complicating Barrett's esophagus: an analysis of cell proliferation

In Japan, cases of Barrett's esophagus with concurrent adenocarcinoma are r elatively rare. We report herein a case of long-segment Barrett's esophagus -associated adenocarcinoma in a 72-year-old Japanese man. The surgical spec imen showed that an ulcerating tumor, measuring 5.5 x 3.9 cm, was present i n the lower esophagus adjacent to the esophagogastric junction, the backgro und lower esophagus having an erythematous appearance. Histologically, the ulcerating tumor was a well-to-moderately differentiated tubular adenocarci noma, with a small area of signet ring cell carcinoma invading the adventit ia. In addition, the esophageal epithelium was replaced by columnar epithel ium (9.5 cm in length) with multifocal dysplastic changes. Immunohistochemi cally, the number of Ki-67-positive cells gradually increased, moving from the normal gastric mucosa (mean Ki-67 labeling index [mKLI], 2.6%) through Barrett's epithelium (mKLI, 12.9%), low-grade dysplasia (mKLI, 16.9%), and high-grade dysplasia (mKLI, 23.7%) to invasive carcinoma, in that order, wi th labeling higher in the invasive tubular adenocarcinoma elements (mKLI, 4 0.5%) than in areas of signet ring cell carcinoma (mKLI, 20.4%). Findings i n our patient suggest that increased cellular proliferation plays an integr al part, in the progression of Barrett's metaplasia to adenocarcinoma. The collection of further cases for analysis will be necessary to confirm this hypothesis.