Published online Apr 28, 2015. doi: 10.3748/wjg.v21.i16.5099
Peer-review started: September 23, 2014
First decision: October 14, 2014
Revised: November 17, 2014
Accepted: January 16, 2015
Article in press: January 16, 2015
Published online: April 28, 2015
Gastric adenocarcinoma is one of the most common malignancies worldwide. Histochemical and immunohistologic analyses classify the phenotypes of gastric adenocarcinoma into several groups based on the variable clinical and pathologic features. A new and rare variant of gastric adenocarcinoma with chief cell differentiation (GA-CCD) has recently been recognized. Studies reporting the distinct clinicopathologic characteristics proposed the term oxyntic gland polyp/adenoma because of the benign nature of the GA-CCD. Typically, GA-CCD is a solitary mucosal lesion that develops either in the gastric cardia or fundus. Histologically, this lesion is characterized by tightly clustered glands and anastomosing cords of chief cells. Immunohistochemically, GA-CCD is diffusely positive for mucin (MUC) 6 and negative for MUC2 and MUC5AC. However, other gastric tumors such as a gastric neuroendocrine tumor or fundic gland polyp have been difficult to exclude. Because GA-CCD tends to be endoscopically misdiagnosed as a neuroendocrine tumor or fundic gland polyp, comprehensive assessment and observation by an endoscopist are strongly recommended. Herein, we report a rare case of oxyntic gland adenoma endoscopically mimicking a gastric neuroendocrine tumor that was successfully removed by endoscopic mucosal resection.
Core tip: Gastric adenocarcinoma with chief cell differentiation is a new and rare variant of gastric adenocarcinoma. Due to difficulty in ruling out other gastric tumors, such as gastric neuroendocrine tumor, fundic gland polyp, or gastric adenoma, comprehensive examination and observation by an endoscopist are strongly recommended. We report a rare case of oxyntic gland adenoma endoscopically mimicking a gastric neuroendocrine tumor that was successfully removed by endoscopic mucosal resection.