Phrenomediastinal echinococcosis.

A patient with the rare presentation of posterior mediastinal echinococcosis is reported. Magnetic resonance imaging (MR) demonstrated the extension of a primary retroperitoneal cyst into the posterior mediastinum which was subsequently confirmed surgically to be of echinococcal origin. Such a case of phrenomediastinal echinococcosis has been described only once before in literature.