the simultaneous occurrence of achalasia and esophageal diverticula is rare.1 there have been few reports of esophageal cancer in achalasia and esophageal diverticula . although most patients with only esophageal diverticula are asymptomatic , patients with both achalasia and esophageal diverticula may present with dysphagia or regurgitation of food.2 additionally , the risk of esophageal cancer is increased in patients with both achalasia and esophageal diverticula . similar to the pathogenesis of esophageal achalasia , chronic inflammation caused by repeated injury and chronic irritation by stagnated food are thought to result in esophageal carcinogenesis.3,4 there have been a few reports of esophageal cancer in achalasia with multiple esophageal diverticula . our group published one such case report in 2009 regarding a case of achalasia associated with multiple large esophageal diverticula.5 this is a follow - up of the aforementioned case , in which esophageal carcinoma was subsequently diagnosed in the diverticula that occurred simultaneously with esophageal achalasia . thus , barium esophagography , esophageal manometry , and esophagogastroduodenography ( egd ) were performed . barium esophagography showed three right - sided esophageal diverticula along the mid - to - distal esophagus with achalasia ( fig . initial esophageal manometry showed aperistalsis in the esophageal body , and each swallow resulted in simultaneous contractions ( fig . the average peak pressure of the esophageal body was 56 mm hg as determined by conventional manometry . therefore , the patient in this case was considered to have vigorous achalasia , defined by an average esophageal body pressure 37 mmhg , rather than the classic form of achalasia associated with lower pressures.6 his symptoms improved after botulinum toxin injection . however , dysphagia , regurgitation of food , and epigastric discomfort recurred 5 years later . a follow - up egd showed a slight increase in the size of the previous diverticula , mild erythematous mucosal changes , and multifocal lugol - voided lesions ( fig . the biopsy result showed a moderate degree of epithelial dysplasia . because the lesions were located in a large and tortuous diverticulum , performing endoscopic submucosal dissection ( esd ) was considered too difficult and dangerous . two months after pdt , egd was repeated to evaluate the response to pdt ( fig . 4 ) . mucosal nodularity was observed at a nontreated diverticulum , which on biopsy was revealed to be squamous cell carcinoma in situ ( fig . the patient underwent an ivor - lewis esophagectomy with regional lymph node dissection for recurrent multifocal esophageal neoplasia , and the final pathologic staging was tisn0m0 ( stage 0 ) . patients with achalasia can develop a variety of complications . among them , the most serious may be esophageal cancer . the overall prevalence of esophageal squamous cell carcinoma in patients with achalasia has been estimated to be 3% , accounting for a 50-fold increase in cancer risk.7 in a recent , large prospective cohort study with long - term ( mean , 15 years ) follow - up data of 448 achalasia patients , the relative hazard ratio for the development of esophageal cancer in achalasia was 28.8 although many cases of esophageal carcinoma in patients with diverticula have been reported , the precise level of cancer risk in esophageal diverticulum remains to be elucidated . in both achalasia and esophageal diverticulum , this food and fluid stasis leads to repeated injury of the esophageal epithelium and chronically irritates the mucosal surface . in addition , bacterial overgrowth and impaired clearance of regurgitated gastric acid contents occur during persistent esophageal distention . due to these diverse factors , chronic inflammation may occur in the esophageal mucosa , which is presumed to develop epithelial hyperplasia , multifocal dysplasia , and finally esophageal cancer.9 before a diagnosis of cancer , the duration of symptoms is usually at least 15 years in patients with achalasia and at least 10 years in patients with esophageal diverticulum . a large prospective cohort study was conducted with a mean follow - up period of 15 years after the onset of achalasia symptoms.8 elderly patients have an increased risk of carcinoma . a diverticulum of less than 2 cm rarely develops into esophageal cancer.10 treatment for esophageal dysplasia or carcinoma arising from achalasia or esophageal diverticulum follows the same principles as esophageal dysplasia or carcinoma without underlying esophageal etiology . esophageal dysplasia or early esophageal cancer can be treated by endoscopic resection , classic endoscopic mucosal resection ( emr ) , and esd , which is widely used . in the present case , however , the diverticula were much too large and tortuous , making emr or esd too risky ; thus , we performed an operation . the optimal time and interval for the surveillance of patients with achalasia and/or diverticulum is open - ended . if a patient presents with newly developed symptoms such as weight loss , melena , or hematemesis , endoscopic evaluation should be performed . regarding achalasia , the current version of the american society of gastrointestinal endoscopy guidelines recommends that surveillance should be initiated 15 years after the onset of achalasia symptoms , although the subsequent surveillance interval is not defined . as in the present case , however , patients with both achalasia and diverticula should be considered for endoscopic surveillance earlier than 15 years , as the earlier development of symptoms necessitates shorter surveillance intervals.11 moreover , clinicians should consider chromoendoscopy or narrow - band image endoscopy as well as white light endoscopy for surveillance of these patients . although the simultaneous occurrence of achalasia and esophageal diverticula is unusual , this case emphasizes the high risk of esophageal carcinoma arising from both etiologies , as well as the importance of early detection by aggressive endoscopic surveillance .