Review ArticlesNon-Neoplastic Mediastinal CystsSyred, Katherine MBBS, FRCPath*; Weissferdt, Annikka MD, FRCPath†Author Information *Department of Pathology, Derriford Hospital, University Hospitals Plymouth NHS Trust, Plymouth, UK †Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX The authors have no funding or conflicts of interest to disclose. Reprints: Annikka Weissferdt, MD, FRCPath, Department of Pathology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Unit 085, Houston, TX 77030 (e-mail: firstname.lastname@example.org). All figures can be viewed online in color at www.anatomicpathology.com. Advances In Anatomic Pathology: September 2020 - Volume 27 - Issue 5 - p 294-302 doi: 10.1097/PAP.0000000000000261 Buy Metrics Abstract 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. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.