Collision carcinoma at the esophagogastric junction: report of two cases.

Two cases of colliding gastric adenocarcinoma and esophageal squamous cell carcinoma are presented. The occurrence of carcinomas of mixed histological type at the esophagogastric junction is uncommon, collision carcinomas being particularly rare. Criteria and problems in the diagnosis of mixed carcinomas are reviewed and discussed. It is suggested that, although undoubtedly uncommon, collision carcinomas at this site may occur more frequently than previously reported.