Achalasia is a disorder of unknown etiology that disrupts esophageal motility and esophagogastric junction outflow. Many long-term complications are associated with achalasia, including progression to megaesophagus and an increased risk for esophageal cancer. While current guidelines recommend against routine screening for cancer in patients with achalasia, many experts believe that routine endoscopic or radiographic screening at a yet-to-be-determined interval could provide essential data beyond evaluating for cancer. Herein, we present a case of stage IVA esophageal adenocarcinoma diagnosed post-esophagectomy in a patient with end-stage achalasia who underwent irregularly spaced, infrequent endoscopic evaluation.