A 68-year-old male who was referred by respiratory medicine for an endoscopic gastrostomy. Upper gastrointestinal endoscopy revealed a flat, reddish lesion (10 × 10 mm) in the gastric antrum area. The biopsy specimen was diagnosed as well differentiated adenocarcinoma. We treated the patient with endoscopic submucosal resection (ESD) . Histopathologic examination revealed gastric-type extremely well-differentiated adenocarcinoma (EWDA) with infiltration of the submucosa.
EWDA is a rare type of gastric adenocarcinoma characterized by its mimicking of normal epithelium. The most important clinicopathologic feature is cancer invasion of the submucosal layer, which is in contrast to its benign microscopic appearance and small diameter.
We have reported a case of gastric adenocarcinoma including extremely well-differentiated adenocarcinoma that was completely resected and diagnosed by ESD.
