Cystic Lesions of the Mediastinum.

Cystic lesions are commonly seen in the mediastinum, and they may arise from virtually any organ. The vast majority of these lesions are benign and result in no symptoms. When large, cysts may produce symptoms related to compression of adjacent structures. The most common mediastinal cysts are pericardial and foregut duplication cysts. Both computed tomography and magnetic resonance are routinely used to evaluate these lesions. Although computed tomography offers superior spatial resolution, magnetic resonance is useful in differentiating cysts that contain proteinaceous material from solid lesions. Occasionally, cysts arise from solid lesions, such as thymoma or teratoma. Although cysts are alike in appearance, location helps narrowing the differential diagnoses.