Imaging description

Superior vena cava (SVC) syndrome is most commonly caused by malignancy [1] which usually causes extensive compression. In this setting, a mass or adenopathy will be seen narrowing or obstructing the SVC on CT images (Figure 59.1). If the cause is from intrinsic thrombosis such as from a central line, enlargement of the azygos vein and/or luminal clot within the SVC can be seen on contrast-enhanced CT (Figure 59.2). In addition to the narrowing or occlusion of the SVC, collateral vessels within the chest can be seen and when present the diagnosis of SVC syndrome [2] can be made.

Importance

The most common cause of SVC syndrome is malignancy, with bronchogenic carcinoma being the most common [1]. Of the bronchogenic carcinomas, small cell lung cancer is the most common [3, 4]. The next most commonly associated malignancy is non-Hodgkin's lymphoma. The most common benign cause is fibrosing mediastinitis. It has been estimated that about 78% of causes of SVC syndrome are due to malignant neoplasms and 22% from benign causes such as fibrosing mediastinitis, radiation fibrosis, or indwelling venous catheters [1]. Recognition of SVC syndrome and identification of its cause will help to lead to quicker resolution or improvement in severity of symptoms.