Different sensitivity to chemotherapy between adenocarcinoma and adenosquamous carcinoma in a case of synchronous multicentric gastric cancer

A 60-year-old man presented with upper gastrointestinal bleeding. We diagnosed double gastric cancer (adenocarcinoma and adenosquamous carcinoma) based on an endoscopic examination. Due to uncontrollable bleeding, total gastrectomy was performed after 4 courses of chemotherapy with S-1 + cisplatin. Histological investigation revealed that no obvious anti-cancer effect was observed in adenosquamous carcinoma (Grade 1), while tumor cells were eliminated in the area of adenocarcinoma (Grade 3). This case clearly demonstrated that sensitivity to chemotherapy was different between adenocarcinoma and adenosquamous carcinoma of the stomach.