Light and Electron Microscopic Study on Metaplasia of Epithelium of Esophago-gastric Junction in Human Adult

Yang, Dae Yul; Nam, Kwang Il; Park, Sung Sik

Abstract

Columnar epithelium-lined esophagus or intestinal metaplasia of the stomach are acquired disorder associated with some pathologic conditions such as reflux esophagitis and gastric carcinoma. The aims of this study were to investigate the characteristics of the metaplastic epithelium in 12 resected specimens of esophago-gastric junction (EGJ) from the patients of gastric carcinoma by histochemistry, immunohistoche-mistry, and electron microscopy. By hematoxylin-eosin staining, metaplasia was found in all 12 cases examined, among them 10 specimens were intestinal metaplasia of the gastric epithelium, 2 cases columnar epithelium-lined esophagus. Intestinal metaplasia was villiform and consisted of columnar cells and mucous (goblet) cells, and showed variations in the pattern of arrangement: metaplasia occurred in EGJ region, occurred in the gastric epithelium apart some distance from EGJ, intermingled with gastric epithelium. The mucous cells of the intestinal metaplasia were stained with both PAS and alcian blue. The gastric epithelium, however, was only stained with PAS. The columnar epithelium-lined esophagus was stained with PAS but not stained with alcian blue. This simple epithelium was positive for 5D3. Interestingly in 2 cases, stratified squamous epithelium was interposed between gastric epithelium. This epithelium was positive for AE8 and was distinguished from gastric epithelium which were positive for 5D3. The columnar cells of the intestinal metaplasia showed regular microvilli, many apical mitochondria, and well developed supranuclear Golgi complex which were characteristic features of typical absorptive cells. The mucous cells were oval in shape and contained numerous mucous droplets in the apical cytoplasm. Intestinal gland consisted of undifferentiated cells and mucous cells, and did not have Paneth cell. Gastric gland consisted of mucous cells of similar fine structural features to those of gastric epithelial cell. Chief cell and parietal cell were not present in the glandular epithelium. These results indicate that most of the metaplasia occurs in the gastic cardiac portion rather than esophageal portion in EGJ, and suggest that the histologic type of metaplsia of gastric epithelium is complete, and that of esophageal epithelium is junctional.