Characteristic pathological findings of achalasia behind unresectable esophageal cancer with pathological complete response after chemotherapy: a case report and literature review

Esophageal achalasia is a rare disease characterized by impaired peristalsis throughout the esophagus, marked esophageal dilation, and nonorganic stenosis of the lower esophagus due to degeneration of the Auerbach’s plexus, and it is a known risk factor for esophageal cancer. To the best of our knowledge, this is the first reported case of achalasia‑associated advanced esophageal squamous cell carcinoma successfully treated using a multidisciplinary approach. A 69-year-old female presented to our department with a 10-yr history of dysphagia and vomiting, accompanied by worsening hematemesis and passage disturbance. Esophagogastroduodenoscopy revealed a protruding lesion with stricture in the mid-to-lower thoracic esophagus, and biopsy confirmed squamous cell carcinoma. Further evaluation revealed unresectable advanced esophageal cancer with multiple lymph node metastases involving the dorsal descending aorta and left supraclavicular region. Following induction chemotherapy, marked shrinkage and disappearance of the primary tumor and metastatic lymph node were observed. However, nonorganic narrowing of the esophagogastric junction, along with esophageal tortuosity and dilation, persisted, leading to a diagnosis of esophageal achalasia. The patient subsequently underwent conversion thoracoscopic esophagectomy with the intent of achieving radical resection. Histopathological examination of the resected specimen demonstrated pathological complete response of both the primary tumor and lymph nodes, resulting in curative resection. Additionally, a reduction in the Auerbach’s plexus and intramural nerve fibers was observed, consistent with achalasia. One year after surgery, paraaortic lymph node recurrence was detected and treated with local radiotherapy. Despite subsequent chemotherapy for recurrence, the patient ultimately died of cancer 25 months after surgery. This case represents a rare instance of conversion surgery achieving pathological complete response following induction chemotherapy for unresectable advanced esophageal cancer associated with achalasia. We report this case with a comparison of histopathological findings to those of other esophageal cancer cases with pathological complete response encountered at our institution, along with a review of the relevant literature.