A ciliated cyst in the posterior mediastinum compatible with a paravertebral Mullerian cyst

Several types of cysts in the mediastinum have been described, such as bronchogenic or thymic cysts and esophageal duplications, most of which arise in the middle or posterior mediastinum close to the tracheobronchial system or the esophagus. We present herein the rare case of a ciliated cyst anatomically distant to the genitourinary organs. An abnormal formation in the posterior mediastinum was incidentally detected on chest X-ray during the preoperative evaluation for a herniorrhaphy in a 54-year-old woman who had a negative medical history. The patient exhibited no clinical signs or symptoms associated with the mass. MRI revealed hypointense signals in T1-weighted scans and homogeneous hyperintense signals in T2-weighted scans. The lesion was resected thoracoscopically and histologic and immunohistochemical stainings showed a ciliated cyst of probable Mullerian origin. Because of their uncertain biological behavior, cystic lesions in the posterior mediastinum should be removed surgically to allow definitive histologic diagnosis.