Is subtyping of intestinal metaplasia in the upper gastrointestinal tract a worthwhile exercise? An evaluation of current mucin histochemical stains.

Intestinal metaplasia is a premalignant condition that occurs in the upper gastrointestinal tract and can be subdivided into three types (I, II and III). Previous studies suggest that type III carries the highest cancer risk. The high iron diamine/alcian blue (HID/AB) technique traditionally has been used to identify this subtype; however, the technique uses reagents that are toxic and potentially carcinogenic. Therefore, in this study we evaluate various alternative histochemical techniques. Our results indicated that the only suitable alternative is Gomori's aldehyde fuchsin/AB technique. The study also revealed that subtyping of intestinal metaplasia is a subjective procedure, open to varying interpretation. Consequently, we suggest that previous work linking cancer risk to metaplasia subtypes should be viewed with some circumspection.