Hydatid cyst: an unusual etiology for a cystic lesion of the posterior mediastinum.

The cystic lesions of the posterior mediastinum include bronchogenic, enteric and intramural esophageal cysts, lymphangioma, and anterior meningocele. Hydatid cysts are usually located in the liver, lung, and brain. Although many uncommon locations have been reported, hydatid cyst has not previously been encountered as an isolated posterior mediastinal lesion. A 4-year-old boy with a posterior mediastinal cystic lesion, which has been proven to be a hydatid cyst, is reported.