Nonmalignant causes of SVCS include mediastinal fibrosis, aortic aneurysm, vasculitis, infections, benign mediastinal tumors, and thrombosis related to the presence of central vein catheters.

Fibrosing mediastinitis (FM) is a rare but serious condition characterized by the abnormal growth of fibrous tissue in the mediastinum, the area between the lungs that contains vital structures ...

This sound is similar to “crackles” that can be heard in the lungs in patients with pulmonary fibrosis. Mediastinal emphysema can occur after esophageal rupture or after cardiac surgery.