Careful withdrawal of the endoscope through the upper esophagus reveals this island of salmon pink colored mucosa surrounded by the normal pearl white colored squamous esophageal epithelium. This is an inlet patch, an island of heterotopic gastric mucosa typically located at or just below the upper esophageal sphincter. These islands are flat and otherwise featureless. They are often missed if not carefully looked for as the scope is removed.
When examined histologically, the low power view demonstrates gastric type mucosa which consists of the foveolar epithelium and gastric body/fundic type glands. At higher power we see glands composed of parietal cells, chief cells and mucinous cells, reminiscent of the gastric body/fundic glands.
The incidence of inlet patch, as demonstrated here in a second example, among the general adult population is not known but is probably between 1-4%. Most patients are completely asymptomatic. Rarely, however, acid production by these inlet patches causes ulceration, strictures, and dysphagia. Adenocarcinoma has also been rarely documented to develop from the inlet patch epithelium. Perhaps related to this observation is the recent report that H. pylori is found colonizing the inlet patch epithelium in 73% of cases. In addition, there are several studies that demonstrate a correlation between the presence of cervical inlet patch and Barrett's esophagus suggesting a possible etiology link.
Peter B. Kelsey, M.D., Harvard Medical School, Massachusetts General Hospital