Non-Neoplastic Mediastinal Cysts.

Primary mediastinal cysts are infrequent lesions that can arise from a variety of mediastinal organs or structures. Most of these are congenital in origin and incidental findings during investigations for unrelated conditions. Histologically, the cysts may be composed of various tissues, including bronchogenic, pericardial, thymic, enteric, Müllerian, lymphatic, and parathyroid types. Mediastinal cysts typically demonstrate a benign clinical course and patients are cured after complete surgical resection. In this review, the embryogenesis, clinical, radiologic, and pathologic characteristics of non-neoplastic mediastinal cysts are examined with discussion of the role of immunohistochemistry and the most pertinent differential diagnosis.