Mediastinal teratoma


Chest x-ray in a child demonstrates a rounded mass projecting over the mediastinum. The descending aorta can clearly be seen through it suggesting the mass is anterior. 

CT confirms that the mass is in the anterior mediastinum. It is well circumscribed, with no evidence of invasion into mediastinal structures. It is composed of a mixture of fat, fluid and soft tissue density material. Features are consistent with a mediastinal teratoma.