J Korean Radiol Soc.  1995 Sep;33(3):373-378.

Cystic Thymic Diseases: CT Manifestations

• Choi YW
• Song SY
• Seo HS
• Jeon SC
• Hahm CK
• Jeon EY

Abstract

PURPOSE
To describe CT findings and differential points of cystic thymic lesions. MATERIAL AND METHOD: We evaluated retrospectively total 19 masses with well marginated cystic lesions at thymic area on CT scans. They were 10 teratomas, 3 congenital thymic cysts, 2 multilocular thymic cysts(associated with thymoma and myasthenia gravis in each), 2 cysts Assciated with thymic Hodgkin's lymphomas an ectopic parathyroid cyst, and an infected thymic cyst. The radiological abnormalities evaluated were thickness of the wall, presence or abscene of septa, mural nodule, solid component, calcification and fat component.
RESULTS
All three cases of congenital thymic cysts and an ectopic parathyroid cyst appeared as thin-walled unilocular cyst with homogeneous internal density and without identifiable solid component. In multilocular thymic cyst, there were thick wall and solid components(n=2), thick internal septa and calcifications(n=l). The cysts of teratomas manifested thick walls(n=9), internal septa(n=4), calcifications(n=6), fat components(n=4), and solid components(n=4). Cysts in Hodgkin's diseases appeared as multilocular or unilocular and had thick wall and septa without calcification. infected thymic cyst presented with multilocular cystic mass with identifiable wall and septa, calcification, and solid components.
CONCLUSION
The thymic diseases with cystic lesion include teratomas, congenital thymic cysts, multilocular thymic cysts, parathyroid cyst, .and Hodgkin's disease. Congenital thymic cyst and ectopic parathyroid cyst are thin-walled unilocular cystic lesions. Cystic lesions associated with teratoma, Hodgkin's disease, and multilocular thymic cyst are thick-walled cystic lesions with or without solid component.

MeSH Terms

Hodgkin Disease
Mediastinal Cyst
Myasthenia Gravis
Retrospective Studies
Teratoma
Thymoma
Tomography, X-Ray Computed