Collision carcinoma at the esophagogastric junction.

Atrue collision carcinoma at the esophagogastric junction is rare. In this article, we report colliding double primary cancers of the esophagus and the stomach in a 68-year-old man and discuss this entity. Pathological analysis after total gastrectomy and partial esophagectomy showed the following findings. Areas of squamous differentiation were found on the esophageal side of the tumor and were adjacent to normal mucosa, and areas of glandular differentiation were found to the gastric side of the tumor and adjacent to normal mucosa. These two tumors collided at the esophago-cardiac junction, but there was no intermingling. In one lymph node, an independent non-intermingled metastatic adenocarcinoma and squamous cell carcinoma were observed. The pathological findings of this case satisfy rigorous criteria for collision carcinoma.