Acutely symptomatic benign mediastinal cysts.

Usually, cystic mediastinal masses are considered as benign. However, the size of the cyst is of importance, chiefly in a closed space such as the superior mediastinum. Rarely a dramatic symptomatology may develop though this was the case in the two patients we describe, who were admitted in the department. In the first case (a parathyroid cyst), the symptoms were due to a thrombosis of the left innominate vein, and in the second case (a thyroid cyst), the severity was dominated by a dramatic compression of the trachea and the vessels. The contribution of computed tomography is nowadays undisputed. It enables the diagnosis of the cystic nature before surgery. The diagnosis can easily be confirmed by percutaneous drainage.