Primary mediastinal echinococcosis.

Computed tomography findings with surgical details are presented in a case of hydatid cyst of posterior mediastinum, a rare site of involvement in echinococcosis infestation. The computed tomography appearance of posterior mediastinal echinococcosis is quite characteristic and can be readily distinguished from other cystic lesions of the mediastinum. Computed tomography provides additional information regarding the involvement of neighboring structures. In this case, computed tomography detected involvement of the descending aorta.