A Case of Collision-type Gastric Adenosquamous Carcinoma at the Esophagogastric Junction

Abstract

A 59-year-old man presented for examination at our hospital after an abnormality was identified on an upper gastrointestinal contrast study during a health checkup. A type 2 tumor was present in the gastric cardia, with invasion of the abdominal esophagus. Cardiac gastric cancer at the esophagogastric junction was diagnosed, the abdominal esophagus was divided transhiatally, and total gastrectomy (with D2 lymph node dissection) was performed. Pathological analysis showed poorly differentiated adenocarcinoma and squamous cell carcinoma, and adenosquamous carcinoma was diagnosed. Adenocarcinoma and squamous cell carcinoma were both present together in a central collision zone, making this a collision-type tumor, a phenomenon that is particularly rare in adenosquamous carcinoma. Because marked lymph node metastasis was present, postoperative adjuvant chemotherapy with S-1 and CDDP was given, and, as of 6 years postoperatively, the patient is surviving recurrence-free. A case of collision-type gastric adenosquamous carcinoma at the esophagogastric junction is presented.