Answer
C. Ependymoma
Comment
Ependymomas are tumors more commonly seen in the central nervous system. However, in unusual circumstances the tumor may also be present in unusual locations such as the posterior mediastinum, probably arising from paravertebral ependymal rests.
It is possible that when the tumor occurs in the mediastinum, it may follow a more protracted course; however, due to the small number of cases described, it is difficult to properly assess its behavior in this anatomic area.
