A 75-year-old man underwent chemoradiotherapy for advanced esophageal cancer. After nine years, he was hospitalized for left pyothorax. Consequently, the patient underwent drainage and window opening surgery. He experienced cardiopulmonary arrest but was resuscitated. Based on cardiac catheterization data, the patient was diagnosed with constrictive pericarditis. Unfortunately, extracorporeal circulation did not improve his condition, and he ultimately died. An autopsy revealed adhesion between the pericardium and pleura, especially the pericardium in contact with the left thoracic cavity, which was markedly thickened. This suggests that constrictive pericarditis, a latent complication of chemoradiotherapy, is aggravated by pyothorax.