Barrett's ulcer. Endoscope view of the lower part of the oesophagus (gullet) of a 79 year-old female patient. This condition has resulted due to Barrett's oesophagus, possibly caused by chronic acid reflux. There is extensive ulceration (some seen at lower left, red) and sever surrounding inflammation. Barrett's oesophagus has caused cells lining the oesophagus to change into cells similar to those which line the stomach, a type of change known as metaplasia. This condition and the resulting ulceration seen may develop into malignant tumours. Management of this condition is difficult and therefore requires frequent monitoring.