Subdiaphragmatic bronchogenic cyst of the esophagus masquerading as a metastatic lymph node of coexisting advanced gastric cancer

Esophageal bronchogenic cysts are rare bronchopulmonary foregut malformations, and those located in the abdominal cavity are particularly rare. Esophageal cysts are typically found incidentally; an exact preoperative diagnosis of bronchogenic cyst is difficult, and surgical resection is generally recommended. Here, we report a case in which a subdiaphragmatic bronchogenic cyst of the esophagus coexisted with advanced gastric cancer. A 44-year-old man was referred for the treatment of gastric cancer. A preoperative examination revealed a mass on the right side of the esophagogastric junction that was preoperatively diagnosed as a metastatic lymph node. Intraoperative exploration revealed that the mass had protruded from the abdominal esophageal wall, and was diagnosed as a cyst originating from the subdiaphragmatic esophagus. The cyst was completely resected with the whole stomach and abdominal esophagus. The histopathological findings of the cyst were specific for a bronchogenic origin. The patient has not shown any signs of disease recurrence.