Solution: Achalasia is an esophageal disorder that is associated with aperistasis and LES dysfunction (failure to relax). Achalasia appears to be a neurogenic disorder and is associated with an extremely dilated esophagus with smooth tapering at the GE junction and no relaxation of the LES. It can be primary, or secondary (generally related to esophageal cancer). In theory, inhalation of amyl nitrate can be used to differentiate the two. WIth secondary achalasia, there will be no relaxation with this, but with primary achalasia, there should be measurable relaxation of the LES related to the smooth muscle relaxation effect of the amyl nitrate. This is generally treated with dilatation if there is no underlying mass.