Caustic alkaline solutions tend to damage the esophagus, and may not even get as far as the stomach. If the esophagus is perforated, a severe mediastinitis may occur. The inflammation can resolve with scarring and stenosis, and that tends to affect swallowing of solids more than liquids, typical for mechanical obstruction. A pharyngeal Zenker diverticulum occurs at a point of weakness in the hypopharynx, most often between the inferior constrictor muscle and cricopharyngeus muscle; it is a pulsion diverticulum from motility problems. Gastric lymphomas may be related to Helicobacter pylori infection (MALTomas) and immune dysregulation. Duodenal ulcerations are predominantly related to H. pylori infection. Megacolon results from marked colonic inflammation or motor disturbances and swallowed substances are not likely to reach the colon unaltered.