[A case of gastric carcinoid tumor with coexisting adenocarcinoma in the same tumor].

A case of a gastric carcinoid tumor with a coexisting adenocarcinoma in the same tumor is reported. The patient was a 71-year-old man who complained of epigastralgia. His physical examination and routine laboratory data were unremarkable. An upper GI x-ray series and the gastroendoscopic findings, however, demonstrated a Borrmann 2-like tumor of the antrum. An endoscopic biopsy specimen from the tumor revealed that it was a gastric adenocarcinoma. Therefore, a subtotal gastrectomy with a lymph node dissection was performed. The resected specimen showed a Borrmann 2-like tumor, but also that infiltration was limited to within the submucosal layer. The pathological findings revealed that the tumor contained two differential component structures (a carcinoid and an adenocarcinoma). The carcinoid and adenocarcinoma structures coexisted with transitional changes that connected both structures. Pathohistologically, it was thought that these two differential components developed from a common origin.