A 25 year old male has a chest x-ray for immigration purposes. This demonstrates a mediastinal mass which displaces the anterior junctional line within the right paratracheal region. Subsequent CT of the chest reveals a well-defined multiloculated cystic lesion measuring 8x10cm with areas of fat, calcification and enhancing septa within it. There is no evidence of invasion.
What is the most likely diagnosis?
Lymphoma | |
Mature teratoma | |
Immature teratoma | |
Thymoma | |
Retrosternal thyroid goitre |
The differential diagnosis above is of an anterior mediastinal mass. Mature teratomas are a type of germ cell tumour which are usually cystic and frequently contain fat and calcification. They are usually discovered incidentally and displace rather than invade surrounding structures. They may become symptomatic when large. Immature teratomas are usually solid. Thymomas may contain fat (thymolipoma) however calcification is not a usual feature in these tumours.