Abnormal performance of peroral endoscopic myotomy (POEM): a case misdiagnosed as achalasia of cardia

Background Pseudoachalasia is a rare disease that behaves similarly to achalasia (AC), making it sometimes difficult to differentiate. Case presentation We report a case of 49-year-old male with adenocarcinoma of the gastroesophageal junction misdiagnosed as achalasia. No obvious abnormalities were found in his initial examinations including upper digestive endoscopy, upper gastrointestinal imaging and chest computed tomography (CT). During the subsequent introduced-peroral endoscopic myotomy (POEM), it was found that the mucosal layer and the muscular layer had severe adhesion, which did not receive much attention, delayed the clear diagnosis and effect treatment, and ultimately led to a poor prognosis for the patient. Conclusions This case suggests that when patients with AC found mucosal and muscular adhesions during POEM surgery, the possibility should be considered that the lesion may be caused by a malignant lesion.