metaplasia typically begins in the antrum- that's kind of the bottom portion of your stomach. And it occurs in response to chronic tissue injury. The cells lining that portion of the stomach change to resemble intestinal
mucosa— the lining of the intestine. So the usual cells that are there don't do what they should be doing. Instead they can even assume some functions found in the intestine - absorptive characteristics.
Intestinal metaplasia is classified histologically as complete (most common) or incomplete. With complete metaplasia, gastric lining in that area is completely transformed into small-bowel mucosa - both in the way it looks and the way it functions. Intestinal metaplasia may lead to stomach cancer, so you need to find out all that you can about your condition.
The atrophic means that it would appear that you're not putting out acid. So if you're on PPIs, it may not be the wisest prescription - talk to your doc.