Carcinoma with multidirectional differentiation arising in Barrett's esophagus.

Four cases of esophageal carcinoma arising in metaplastic Barrett's epithelium are presented in which multidirectional differentiation was demonstrated by light and/or electron microscopy and immunohistochemistry. All tumors and adjacent mucosa produced both neutral and acidic mucins, as well as one or more hormones indigenous to the gut, including gastrin, bombesin, substance P, somatostatin, and serotonin. Gastrin and somatostatin were the peptides most frequently identified in the tumors, while somatostatin and serotonin predominated in Barrett's epithelium. Ultrastructurally, neurosecretory-type granules, 80-250 nm in diameter, were present in 2 cases; squamous features also were present in one of these cases. One patient displayed hypertrophic osteoarthropathy, which disappeared after the tumor was resected. These cases represent the majority of the Barrett-associated carcinomas in our material. Compared to the "pure" esophageal adenocarcinomas not included in this report, these tumors behaved more aggressively, with wider local involvement and nodal and systemic metastases at the time of presentation. The incidence of multidifferentiation in esophageal carcinomas is not known nor is its possible significance, particularly with regard to tumors arising in metaplastic epithelium. This group may merit further study to detect true differences, if any, between these esophageal carcinomas and their apparently more common counterparts.