Scanning electron microscopy of mucosal biopsies of the human upper gastrointestinal tract

There have been comparatively few scanning electron microscopic studies of mucosal biopsies of the human upper gastrointestinal tract. This report deals with the results of scanning electron microscopy of 21 mucosal biopsies: 7 esophageal, 2 from the gastroesophageal junction, 3 gastric and 9 duodenal biopsies. Mucosal biopsies were obtained at the time of fiberoptic endoscopy and were placed immediately into 2.5% glutaraldehyde in phosphate buffer, pH 7.4. After post-fixation and removal of mucus, tissue was processed by means of the O-T-O method, Dehydrated, critical point dried with CO2 and examined at 20kV. Scanning electron microscopy (SEM) of mucosal biopsies of the esophagus shows a mosaic pattern. Cell borders are clearly demarcated and there are find microridges on the luminal surface. There are varying degrees of detachment and desquamation of the superficial cells. Acute esophagitis was observed in 2 of the biopsies. At the gastro-esophageal junction, the squamous epithelium of the esophagus abuts in a jagged manner upon the columnar epithelium of the stomach. The SEM appearance of the gastric mucosa is characterized by the presence of hillocks with central depressions formed by the gastric pits. Flattening of the hillocks and invagination into the gastric pits were seen in a biopsy of a fold at a Billroth I anastomosis. The villi of the duodenal mucosa form tongue-like of finger-like projections. The luminal surface of the absorptive cells has a dense covering of microvilli. The openings of goblet cells are studied on the mucosa as minute depressed foci. Varying degrees of an acute inflammatory reaction were present in 5 duodenal biopsies. It is concluded that SEM should prove to be of value as an aid in the diagnosis of mucosal biopsies of the human upper gastrointestinal tract.