A 23 year old woman came with a swelling on the left side of the neck since six months
The frontal chest radiograph shows a well defined, circular soft tissue opacity in the left upper zone . Its upper margin merges inpercitibky with the soft tissues of the neck. The trachea is displaced to the right. The contrast enhanced CT scan of the neck shows a well defined, lobulated enhancing lesion measuring 3.8× 6.1×7.8 cm in the left infrahyoid region extending into superior mediastinum . The lesion splays the proximal common carotid artery and the internal jugular vein.