Oesophageal inlet patch. Endoscopic image of an inlet patch (red, top) on the lining of a patient's oesophagus (gullet). An inlet patch is a congenital abnormality consisting of a patch of stomach lining (gastric mucosa) tissue in place of the usual oesophageal lining at or just after the upper esophageal sphincter, where the oesophagus meets the stomach.