Clinicopathological features of gastric adenocarcinoma of the fundic gland (chief cell predominant type) by retrospective and prospective analyses of endoscopic findings.

Background and Aim: Gastric adenocarcinoma of the fundic gland type (chief cell predominant type) (GA-FG-CCP) is a variant of gastric adenocarcinoma with chief cell differentiation. GA-FG-CCP is rare and not well understood. The present study aimed to investigate the clinicopathological features of GA-FG-CCP using retrospective and prospective analyses of endoscopic findings.
Methods: A total of 20 patients including nine cases treated with endoscopic submucosal dissection (ESD) were diagnosed with GA-FG-CCP. Morphological changes were analyzed by retrospectively retracing past endoscopic records and following up after definitive diagnoses, including the status of Helicobacter pylori (H. pylori) infection.
Results: GA-FG-CCP were small and whitish lesions accompanied by atypical vascular growth and their macroscopic types were classified as 0-IIa (60%), 0-IIb (25%), and 0-IIc (15%), respectively. The lesions were found in the non-atrophic gastric mucosa of the upper (70%) or middle portion (30%), although gastric mucosal atrophy associated with current or past H. pylori infection was identified in 75% of cases. In the nine cases treated with ESD, submucosal invasion was identified in 80% of the resected lesions, but no lymphovenous infiltration was detected. Ki-67 labeling index of GA-FG-CCP was low at 3.2% and visible morphological changes were rarely detected during long-term endoscopic observation for 58.9 ± 13.1 months.
Conclusions: These data indicate that GA-FG-CCP, even when submucosal invasion occurs easily, might be of low-grade malignancy as long as it is the chief cell predominant type without other epithelial abnormalities. In addition, GA-FG-CCP might develop despite H. pylori infection or gastric mucosal atrophy.
(© 2016 Japan Gastroenterological Endoscopy Society.)