Endocrine cells and lysozyme immunoreactivity in the gallbladder

A total of 89 gallbladders with various conditions were examined histologically and immunohistochemically to detect various kinds of metaplastic changes. The gallbladder mucosa of the fetus and normal gallbladder showed no metaplastic changes. In 32 cases of chronic cholecystitis, metaplastic changes, such as mucous gland metaplasia (23 cases), Paneth's cells (six cases), and goblet cells (four cases) were observed. All cases containing Paneth's cells or goblet cells showed simultaneous lysozyme immunoreactivity and also contained argyrophilic cells. Among 23 cases with mucous gland metaplasia, 15 cases showed lysozyme immunoreactivity, eight contained argyrophilic cells, and 16 showed lysozyme immunoreactivity and/or argyrophilic reaction. The other seven cases showed only mucous gland metaplasia without endocrine cells or lysozyme immunoreactivity. These results suggest that the presence of lysozyme and/or endocrine cells is a conventional marker of gastrointestinal metaplasia of the gallbladder mucosa. Using these markers, 14 (28.6%) of 49 cases of adenocarcinoma of the gallbladder contained endocrine cells; 18 (36.7%) showed lysozyme immunoreactivity; and 25 (51.0%) contained at least one marker of endocrine cells or lysozyme immunoreactivity. These results suggest that at least half of adenocarcinomas of the gallbladder might be derived from metaplastic changes.