Microscopic examination reveals a markedly thickened mucosa with hyperplasia (folveolar) and cyst formation. In addition, there is focal atrophy of the gastric glands. In some areas the gastric pits extend all the way down to the muscularis mucosa, and are focally dilated with mucus. Focal areas of pseudo-invasion through the muscularis mucosa are seen. While there is significant architectural distortion, there is no dysplasia. Nor is there any substantial inflammatory component.