A ciliated cyst with müllerian differentiation arising in the posterior mediastinum.

Primary congenital mediastinal cysts are rare, have a broad range of etiologies, and can be bronchogenic, thymic, neuroenteric, or esophageal in origin[1]. Recently, Hattori[2] described the first case of a ciliated cyst of probable Mullerian origin arising in the posterior mediastinum, a so-called Hattori’s cyst. Since that time, several additional cases have been reported[3,4]. We found a posterior mediastinal cyst with Mullerian differentiation that was consistent with previous description of Hattori’s cyst. To our knowledge, this is the first report of Hattori’s cyst arising in the posterior mediastinum in Korea.