An important finding for differential diagnosis in thymic cyst mimicking pericardial cyst: punctate calcification.

Mediastinal cysts are usually congenital but present in adulthood. A pericardial cyst is usually localized in the right cardiophrenic region. Thymic cysts are less common and are located in the cervical region or anterior mediastinal region. While thoracoscopic excision or aspiration can be applied in pericardial cysts, excision is recommended in thymic cysts. We present a case of a thymic cyst located in the localization of the pericardial cyst and radiologically containing wall punctate calcification.