Thymic Cyst

Etiology: derived from the thymopharyngeal duct so may occur anywhere along site of embryologic descent of thymus from mandible to level of diaphragm
Imaging: cystic lesion in thymus
Clinical: become symptomatic and enlarge dramatically when hemorrhage occurs

Radiology Cases of Thymic Cyst

CT of thymic cyst — Axial CT with contrast of the chest shows a multiseptated cystic mass in the anterior mediastinum.

CXR and CT of thymic cyst — CXR AP shows an abnormal contour to the left superior mediastinum in the region of the aortic arch which is too prominent for the patient’s age. Axial CT with contrast of the chest shows a low density lesion within the thymus compressing the brachiocephalic vein.