Abstract
A 64-year-old man found in gastroscopy to have a submucosal gastric lesion 2cm in diameter was found in en-hanced computed tomography (CT) to have a cystic tumor in the gastric wall. We conducted tumor resection under laparotomy. Histological findings showed gastric mucosa in the internal mucosa of the cyst, and 2 mu-cosal layers were divided from each other by 2 muscularis mucosa layers. In one part of the internal mucosal layer, adenocarcinoma had arisen, but had not invaded the outer layer, so we diagnosed the man as having early gastric cancer arising in the gastric duplication cyst. Such malignant changes thus should be considered in the diagnosis of cystic gastric lesions.
