Complete and incomplete pyloric gland metaplasia of human gallbladder.

The features of pyloric gland metaplasia in the gallbladder epithelium were studied by histochemical staining for mucin and the immunoperoxidase method for pepsinogens (Pg) I and II. Pyloric gland metaplasia was found in 48 of 72 gallbladders removed surgically. All the pyloric gland metaplastic cells contained class III mucin demonstrated by paradoxical concanavalin A (Con A) staining. Pyloric gland metaplasia was classified into complete and incomplete types on the basis of the immunohistochemical reactivities of Pgs I and II: The complete type of pyloric gland metaplasia contained neutral mucins and weak Pg I and strong Pg II activities, like normal pyloric gland cells. Almost all specimens of the incomplete type of pyloric gland metaplasia contained acid mucins and were further classified into two types: an incomplete type 1, which had Pg II but no Pg I activity, and an incomplete type 2, which had no Pg I or II activity.