Barrett's adenocarcinoma. Endoscope view of a cancerous tumour (neoplasm, far right) in the lower part of the oesophagus (gullet) of a 75 year-old patient. This type of cancer (adenocarcinoma) arises from glandular tissue in an organ's epithelium (lining). This condition has resulted due to Barrett's oesophagus, possibly caused by chronic acid reflux. Barrett's oesophagus causes cells lining the oesophagus to change into cells similar to those which line the stomach, a type of change known as metaplasia. Prognosis for this condition is poor, treatment involves surgical removal, but only offers 20% survival over five years.