[Adenocarcinoma arising in a bronchial cyst of the mediastinum].

A 39 year-old man with a mediastinal tumor was operated on. After the median sternotomy incision, a mediastinal cyst, which was connected to the right pulmonary hilus with a string, was found. The microscopic examination of the cyst revealed a bronchial cyst with ciliated columunar epithelium and muscle fibers. Adenocarcinoma was found in the mucosa of the cyst. This patient seemed to be the first reported instance of carcinoma in a mediastinal bronchial cyst.