Biopsy proven Barrett esophagus (no histologic dysplasia). This is more than an incidental finding on an oesophagram -- this is a critical finding. By the time you find a lobulated esophageal carcinoma it's too late; the patient needs to be treated and followed at the first signs of metaplasia in the normal esophageal stratified squamous epithelium.
It is important to get enough air/gas in the esophagus in order to optimize one's double contrast technique and pick up subtle findings like this. In addition to effervescent granules, it is often helpful to tell the patient to swallow as much air as possible while drinking the barium.
In this example, the Barrett esophagus is at the gastro-esophageal junction, but it can occur in patches anywhere from the mid-esophagus down to the gastro-esophageal junction.