There are several possible reasons for thickening of the stomach lining. Infections may possibly be involved, and other repeated irritation of the lining such as some medication. Excess acid production, and some hormonal influences can also play a part.
There are some stomach cancers of the lining or stomach muscle layer which can appear as thicker areas, and there is a disorder called Menetriers Disease which is a benign condition where the inner lining grows.
You will need further tests such as endoscopy, H.Pylori test, and possibly biopsy of the affected area.
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