Cysts and cyst-like formations of the mediastum: clinical and radiological manifestations

. Mediastinal cystic formations are well-shaped, often round formations that contain fluid and are lined with epithelium. The main cystic formations include congenital benign cysts (bronchogenic, duplicating the esophagus, neuroenteric, pericardial and thymic cysts), meningocele, mature cystic teratomas and lymphangiomas. Many tumors (e.g., thymomas, Hodgkin's disease, germ cell tumors, mediastinal carcinomas, lymph node metastases, nerve root tumors) may undergo cystic degeneration, especially after radiation or chemotherapy, and show mixed solid and cystic elements on computed tomography (CT) or magnetic resonance imaging (MRI), as well as acquire the structure of cavity formations during the tumor destruction. If the degeneration is extensive, such tumors may be virtually indistinguishable from con­genital cysts. However, the history of the disease, visualization of the anatomical location of the formation, some details visible on CT or MRI, allow in many cases to make the correct diagnosis. Familiarity with the radiographic features of mediastinal cystic lesions facilitates accurate diagnosis, differentiation from other cystic lesions, and thus ensures optimal treatment of a patienta.