A Case of Esophageal Squamous Cell Carcinoma Detected After Peroral Endoscopic Myotomy in a Patient With Achalasia.

Achalasia, a chronic esophageal motility disorder, increases the risk of esophageal squamous cell carcinoma. Despite effective treatment with peroral endoscopic myotomy (POEM), patients remain at risk of malignancy. We present the case of a 75-year-old Japanese woman diagnosed with achalasia who was found to have esophageal squamous cell carcinoma three months after POEM. Early detection through endoscopic surveillance and biopsy led to successful endoscopic submucosal dissection. This case underscores the need for ongoing surveillance of patients with achalasia post-POEM to ensure early identification and treatment of potential malignancies.