Irregular Z-lines in the esophagus are displacements of the stratified squamous epithelium and the columnar epithelium in the tube that connects the stomach to the throat. The National Institutes of Health state that irregular Z-lines typically lead to a diagnosis of Barrett's esophagus.
According to the NIH, endoscopic ultrasounds are used by medical professionals to determine whether an esophagus is irregular. An esophageal Z-line is irregular if it does not correctly join with the gastroesophageal junction at the base of the esophagus. Barrett's esophagus is typically diagnosed if the ultrasound reveals an irregular Z-line, but doctors usually conduct biopsies to detect the presence of intestinal cells in the esophagus mucosa. WebMD sites that Barrett's esophagus develops when the symptoms of gastroesophageal reflux disease become severe. The symptoms of GERD include heartburn, stomach aches and unpleasant throat sensations. When a person has Barrett's esophagus due to complications of GERD, the tissue in the esophagus becomes similar to the tissue that lines the intestine. This happens because an esophagus with an irregular Z-line cannot properly restrict the uptake of digestive acids. Only 10 percent of people with GERD develop Barrett's esophagus, but its presence could lead to cancer in the esophagus, esophageal adenocarcinoma.