Giant primary mediastinal hydatid cyst causing Horner's syndrome: report of a case.

As the liver and the lungs are the most common sites for hydatid cysts, a primary mediastinal involvement is quite rare. The symptoms related to primary mediastinal hydatid cysts usually depend on the size, location and compression to nearby structures. Presenting a 51-year-old male patient with the symptoms of Horner's Syndrome, we draw attention to a rare complication of a giant primary mediastinal hydatid cyst and its challenging management.