Adenocarcinoma arising in a mediastinal enteric cyst.

A 39 year-old male was admitted to our hospital because of relapsing episodes of pneumonia. His chest roentgenogram showed a consolidated shadow and cavity formation in the left lower lobe. During a left lower lobectomy an enteric cyst in the posterior mediastinum involving lung was found. This cyst in the lung contained normal gastric parietal cells and pancreatic tissue, and was surrounded by adenocarcinoma characteristic of gastric cancer. This is a rare case in which an adenocarcinoma arise from an enteric cyst in the mediastinum.