Superior Vena Cava Syndrome

Clinical History: Patient with known pulmonary metastatic disease.
Findings: Serial axial images were obtained through the chest after administration of IV contrast. Multiple serpentine vessels are visualized in the left anterior and posterior chest walls. Contrast is also visualized within the azygos vein, there is also dilatation of the azygos vein. There is no contrast visualized in the superior vena cava and there appears to be a hypodense abnormality within the lumen. This most likely represents thrombus. A catheter tip is visualized passing through the center of this thrombus. Metaport catheter is visualized in the subcutaneous tissue of the left anterior chest wall. There were numerous pulmonary nodules visualized in both lung fields. Evidence of bilateral pleural effusions.
Diagnosis: Superior Vena Caval (SVC) Syndrome
Discussion: Superior vena caval obstruction otherwise known as SVC syndrome which is secondary to obstruction of the SVC with development of collateral pathways. The etiology is either a malignant or benign lesion. Malignant lesions account for (80% to 90%) of such occurrences with bronchogenic carcinoma accounting for greater than (50%) followed by lymphoma. Benign causes include granulomatous mediastinitis (usually histoplasmosis, sarcoidosis, TB). Other benign etiologies include substernal goiter, ascending aortic aneurysm, and constrictive pericarditis.
Collateral routes include esophageal venous plexus which are also known as (downhill varices). In addition, azygos and hemiazygos veins. Also accessory hemiazygos and superior intercostal veins. Lateral thoracic veins and umbilical veins can also be visualized. In addition, vertebral veins. Patients may present with head and neck edema, cutaneous enlarged venous collaterals, headache, dizziness, syncope. With benign etiology there is a slower onset and progression. With malignancy, there is rapid progression within weeks. Radiographic manifestations include superior mediastinal widening. In addition, encasement, compression, and occlusion of the superior vena cava. One may see dilated cervical and superficial thoracic veins. In addition, thrombus within the superior vena cava as in this case may also be present.
References:Dahnert, Wolfgang: Radiology Review Manual, SecondEdition, 1993, Pg 409, Williams and Wilkins.